============================== >> USING HELP << =============================
                                                                              
       (Throughout the help files Deep Space 3-D is referred to as DS3D)      
                                                                              
 QUICK HELP -- is an alphabetical listing of some of the things you might want
 to do with DS3D along with sequences of key strokes you would use to         
 accomplish your goals.                                                       
                                                                              
 EXTENDED HELP -- also gives suggested keystrokes, but Extended Help is as    
 much an astronomy handbook, as it is an instruction manual.  The topics are  
 in narrative rather than alphabetical order.  To get full value out of DS3D  
 you should print out the the help notes, at some point, and read through     
 them.                                                                        
                                                                              
                                                                              
 Abbreviations used in the both Extended Help and Quick Help:                 
      Mm = Main Menu, initial menu in text mode                               
      Dm = Display Menu, initial menu in graphics mode (top left corner)      
      <  > = a single keystroke, such as <Enter>, <SpBar>, <Arrow>, etc.      
      [ , , ] = a sequence of keystrokes used to achieve the stated purpose   
                                                                              
 Conventions:                                                                 
      <Enter> = Used to terminate a number or word entry or to accept a       
         default command                                                      
      <SpBar> = Used to toggle a check mark on or off in a selection menu     
         (any number of items may be selected in this kind of menu)           
      <Esc> = Exit or retreat to previous menu                                
      (../../..) = Choose one, (such as (Y/N), (A/B/C), etc.)                 
      <PgUp/Dn> = in zoom mode [Dm, F3, F1], or 3-D mode [Dm, F9, (F1/F2)] to 
         change size of zoom box; in text mode, to jump up or down one page   
      <PgDn> = During data entry, accept all defaults and jump to last item   
      <Up/Dn Arrow> = During data entry, go to previous or next item (even if 
         the items are arranged side-by-side.                                 
      <Lt/Rt Arrow> = used to position the cursor within an item for editing  
         purposes                                                             
                                                                              
      When in doubt about what data value to use, accept default value.       
      When in doubt, use the <Esc> key to quit an item.                       
                                                                              
                                                                              
 ======================== >> OVERVIEW FOR BEGINNERS << =======================
                                                                              
 DS3D was designed to be a general purpose star mapping tool that would meet  
 the needs of experienced observers, but it is also well suited to the needs  
 of beginners.  Beginners, more than anyone else, need accurate maps that show
 exactly what to look for, and where and when.                                
                                                                              
 Your first goal should be to learn to recognize some of the constellations.  
 The constellations are your stepping stones.  You will be using them to find 
 your way around the sky.  They lead you to all kinds of beautiful sights in  
 binoculars and telescopes.  You don't have to learn the constellations all at
 once.  Start with the ones containing the brightest stars.  These will serve 
 as a framework for the sky.  You can fill in the details at your leisure.    
                                                                              
 The first thing you should do with DS3D is explore it.  Read through the     
 Quick Help and try out the options.  When you are ready to do some real      
 observing you will need to set your observing site.  In the site list        
 distributed with the program there are a few popular star party sites        
 followed by a list of general regional sites.  The latter are intended to    
 help get you started quickly.  If you don't know your latitude and longitude,
 pick the general regional site closest to you.  Sooner or later you should   
 consult a map, an almanac, or ask at your city hall or the library reference 
 desk for more exact data.                                                    
                                                                              
 The chart that will probably best help you learn the constellations is the   
 Circular Day-and-Time map.  Here is a step-by-step guide for producing one:  
                                                                              
 --Display the Default Map [Mm, Display Star Chart].                          
                                                                              
 --Select Special Maps, option C for a Circular Day-and-Time map [Dm, F2, C,  
 ...].  If you want larger scale printouts, choose the Horizon-View map       
 instead (option H instead of C), and make four of them: one each for north,  
 south, east, and west.                                                       
                                                                              
 --Filter out the constellation lines so only the bright constellations are   
 shown [Dm, F5, F1].                                                          
                                                                              
 --Add the bright planets [Dm, F6, F1, F1], identify them [Dm, F6, F3], and   
 learn to recognize their symbols.  (Sometimes no planets are visible, so     
 don't be concerned if none are displayed.)  The bright planets look like     
 stars.  They are as bright or brighter than the brightest stars.             
                                                                              
 --Add constellation names [Dm, F5, F4] and cycle through the list,           
 positioning them [<Arrow Keys>, <Enter>] until they don't interfere with the 
 detail you want to see on the map.                                           
                                                                              
 --Abbreviations for the names are shown on the screen, but the full names    
 will appear on the printed map and will be the size indicated by the boxes   
 that appear as you move the names around.  If you want to use abbreviations  
 on the printout type <PgDn> during the positioning cycle.  Type <PgUp> if you
 want to restore all names to their full length.                              
                                                                              
 --If a constellation contains only faint stars and you want to ignore it     
 until later, delete the name.                                                
                                                                              
 --When you are finished with the naming process you can remove the unnamed   
 constellations if you wish [Dm, F8, F1, Y].                                  
                                                                              
 Now go outside.  Hold the chart overhead with the top pointing north.  Read  
 the chart with a small flashlight, preferably one with a red filter to       
 preserve your night vision, but any small flashlight will do at this point   
 since you will be concentrating on the bright stars.  Identify the brightest 
 stars and any bright planets that are in the sky.  The important thing is to 
 take the chart outside at night and use it!  You will be surprised how easy  
 it is to recognize the constellations when you have an accurate star chart.  
 Once you find a constellation, look for it again each night until you can    
 recognize it immediately.  It won't take many nights before you know your way
 around the sky.  Continue the process through the year as the seasons change,
 or wait up later at night for a new crop of stars to rise over the eastern   
 horizon.                                                                     
                                                                              
 The moon is another obvious starter object.  Notice how the moon moves and   
 changes phase during the month [Dm, F6, F1, F3, Moon], choose 1 day intervals
 for about 27 days with the 'S' option.)  The phase of the moon is directly   
 related to its position in the sky.  Look at the moon with binoculars or a   
 telescope to see its craters, mountains, and lava planes.  "Relief" features 
 are best seen along the "terminator" (the line between day and night) where  
 shadows are the longest.  The location of the terminator changes each night, 
 revealing different slices of the moon throughout the month.  Choose [Mm,    
 Almanac] to compute the moon phases throughout the year.  Go out within 4 or 
 5 days either side of first quarter if you want to observe the moon in the   
 evening sky.  When the moon is up it washes out most of the sky, so choose   
 dates near New Moon for prime observing of fainter objects throughout the    
 night.  A third quarter moon will not rise until about midnight, so around   
 third quarter you will have a dark sky during the first half of the night.   
                                                                              
 Whether the moon is out or not, you will be able to see the bright planets   
 Venus, Mars, Jupiter, and Saturn, whenever they are in the sky.  Plot their  
 locations for a given night [Dm, F6, F1, F1] or individually over a range of 
 dates.  In plotting for a range of dates if you choose the "H" or "B" option,
 while you are on the Default map or a Circular Day-and-Time or Horizon View  
 map, it will plot X's to indicate how the planet will move relative to the   
 horizon as the planets and stars together drift westward from night to night.
 Mercury is also bright, but it must be seen when it is farthest from the sun.
 Plot Mercury with the "H" or "B" option to see how it moves relative to the  
 horizons over several weeks or months.  Step through with [Dm, F6, F3,       
 <Enter>, <Enter>, etc.] to identify the dates when it will best be visible in
 the evening or early morning sky.  West-facing (pm) or East-facing (am)      
 Horizon maps [Dm, F2, H, West/East] work well as a Mercury finder charts.    
                                                                              
 The best "first telescope" is a pair of binoculars!  Pick a moonless night   
 and go to the best dark sky location you can manage.  Print out an all-sky   
 map ahead of time.  Take a flashlight covered with a red filter to be able to
 read the maps without destroying your night vision.  For an excellent filter,
 find an art or drafting supply store and ask for "Ruby Lith".  If you have a 
 laptop computer, get enough to cover the screen also for nighttime use.  When
 you get to your dark sky site, scan the sky with your binoculars,            
 particularly along the Milky Way and look for little "cotton balls,"         
 "smudges," and resolved star clusters.  Mark them on your map and try to     
 identify what you saw by displaying the brighter deep sky objects [Dm, F7,   
 F1].  Limit the list to about 9th or 10th magnitude for binocular objects.   
 Select everything in the left-hand column.                                   
                                                                              
 On your second try, plot out some of the brighter objects ahead of time and  
 look specifically for them.  The constellations you learned will become more 
 meaningful as you use them to find your way around the sky to locate objects 
 of interest.  In the summer sky concentrate particularly along the Milky Way 
 in Scorpius and Sagittarius through Cygnus.  These areas are rich with star  
 clusters and nebulae.  In the fall the Andromeda and Triangulum Galaxies (M31
 and M33) are excellent targets for binoculars.  In the winter be sure to scan
 the Milky Way from Cassiopeia and Perseus through Canis Major and Puppis.    
 Plot the center line of the Milky Way on your all-night map using the Grid   
 Lines feature [Dm, F5, F6, Galactic Equator (and omit all other grid lines)].
                                                                              
 Write to us for the book, "Exploring the Night Sky with Binoculars" and the  
 planisphere, "The Night Sky," both by David Chandler (see [Mm, Catalog &     
 Order Form].  Subscribe to Sky and Telescope and/or Astronomy Magazine to    
 start building your background and awareness of the sky and astronomical     
 events of interest.  Use the Search option [Dm, F7, F5] to find objects in   
 the sky mentioned in your reading.  You will find that the more you learn    
 about astronomy, the more useful DS3D will become.                           
                                                                              
                                                                              
 ======================== >> OVERVIEW FOR TEACHERS << ========================
                                                                              
 I have taught high school science and math and occasional community college  
 courses over the past 20 years.  Programming has been what I do late at night
 and during vacations.  Many of the features of DS3D have been motivated by my
 classroom experience.  I have built whole courses around activities produced 
 with DS3D and Planet Tracker.                                                
                                                                              
 (Planet Tracker is specifically addressed to teachers.  It presents many ways
 to view and understand planetary motion through printouts and on-screen      
 animation, with conceptual understanding as the goal.  It comes with an      
 extensive on-disk "lab manual" containing activities for classrooms with or  
 without a computer on site.  A demo copy is available for $5.  See [Mm,      
 Catalog & Order Form].)                                                      
                                                                              
 How can you use DS3D for an astronomy unit?  Try these suggestions for       
 starters:                                                                    
                                                                              
 (...if you make regular use of DS3D in your classes, please find it in your  
 budget to register your copy.  If you make it available for multiple machines
 or put it on a network, please obtain the site license.  Feel free to give   
 shareware copies to interested students and colleagues.)                     
                                                                              
 --Blank Star Maps -- If students can find the constellations on star maps    
 with nothing but dots, they can find them in the sky.  Start them with the   
 Circular Day-and-Time map for the current date [Dm, F2, C, ...].  Limit the  
 magnitude to about 4.5.  Print out one copy with lines and labels, and       
 another with the everything but stars removed [Dm, F8, F9].  Teach them the  
 bright stars first.  Have them use the charts at night.                      
                                                                              
 --Match-the-Sky Maps -- Your students will love making and using Star Frames.
 Bend a coat hanger into a rectangle with the hook made into a loop/handle at 
 one corner.  Cover it with plastic wrap.  Print out Match-the-Sky Maps of    
 prominent constellations to be used as masters [Dm, F2, M, ...].  Trace the  
 main dots for the constellation onto the plastic wrap with white correction  
 fluid or luminous paint (available from hobby shops or electronics shops).   
 Make a whole set for the main constellations one time of year and have a     
 schoolyard star party.                                                       
                                                                              
 --I know one 4th grade teacher who did a mural of the zodiac across the whole
 back wall of his classroom and had his students update the positions of the  
 sun, moon, and planets each day.  You could do the same thing with orbits.   
 Make transparencies from printouts and project them on butcher paper with an 
 overhead projector.                                                          
                                                                              
 --One celestial body (besides the sun) that can be observed during the school
 day is the moon.  For planning purposes, go to [Mm, Set Day and Time], set   
 the observing time for the hour of the day you want to do the activity, then 
 plot a Circular Day-and-Time map [Dm, F2, C, ...].  The constellations will  
 be "wrong" for that time of year because these are the stars out when        
 daylight obscures them.  Now plot the sun and moon for a one month period    
 [Dm, F6, F1, F3, 1, 28, B, Sun, Moon, Y].  There will be progressively more  
 offset between the moon images and the X's, since the background stars shift 
 about a degree per day.  The X's show where to expect the moon, the          
 corresponding image shows the phase.                                         
                                                                              
 --Another instructive printout involving the moon is to print out its        
 position at 1/10 day intervals for several days (about 30 positions).  Note  
 that it does not move in a smooth path.  This is because your position on the
 earth is taken into account and as the earth spins you are moving forward and
 backward relative to the motion of the moon.  It is the closeness of the     
 moon that makes this effect visible.  In fact it is from this kind of data   
 that Tycho Brahe (in the 16th century) was able to measure the distance to   
 the moon.  The lack of this kind of irregularity in the motion of comets is  
 what led him to conclude that they were farther from the earth than the moon.
                                                                              
 As a simplified measurement, find a date when the moon is crossing the       
 equator.  Print out the positions of the moon as seen from the north and     
 south poles.  (Be sure to set each for 0 degrees longitude and the same time 
 UT.)  The shift of the moon in the sky is equal to the angular size of the   
 earth as seen from the moon.  (Try drawing a sketch of this situation if it  
 seems confusing.)  Compare this shift with the apparent size of the moon,    
 which is the angular size of the moon as seen from earth.  You should come   
 out with about a 4:1 ratio, which says the earth is about four times as large
 as the moon.  Tycho did not have the luxury of traveling to different parts  
 of the earth, or communicating with someone in the opposite hemisphere, so he
 had to let the earth carry him around and use the more subtle variations in  
 the moon's motion instead.                                                   
                                                                              
 --Teach constellations then show the stars in 3-D.  Certain questions arise  
 naturally.  Why can't we see the constellations in the sky like in the 3-D   
 views?  Why does the sky appear to be a dome rather than open space?  (The   
 answer is our depth perception fails at great distances, so beyond a certain 
 distance everything looks the same distance away.  If everything appears to  
 be the same distance away, we see ourselves to be at the center of an sphere.
 The sky is an illusion.  There is no sky!)  To reinforce the concept do      
 activities with 3-D photography.  Take a picture of a stationary scene.  Move
 to one side a few inches or a few feet and take another picture.  Increasing 
 the distance between the two viewpoints increases the depth perception.  Look
 at the pictures under a stereo viewer, one picture for each eye.  (Get       
 wallet-size prints or crop the pictures to fit together with the same        
 separation as the lenses in the stereo viewer.)  What would space look like  
 if we were giants with eyes half a light year apart?  That is exactly what   
 the 3-D printouts show.  (We give price breaks for 20 or more stereo viewers 
 classroom sets.)                                                             
                                                                              
 --Many hospital workers will tell you there are more births at full moon     
 than at other times of the month.  Is it a myth?  Check it out.  Print out   
 the moon phase data in the [Mm, Almanac] option for the range of years when  
 your students were born.  Have each student figure out how many days past new
 moon they were born.  Make a chart.  Is there a pattern?  Enlarge the sample.
 Do patterns emerge or disappear when different classes are sampled?  What    
 about when the data are combined?                                            
                                                                              
 --Why isn't every new moon a solar eclipse?  Print out an almanac for the    
 year.  Use the [Mm, Set Day and Time] option to set the time for each        
 successive new moon.  Plot the planets on the Default Map and zoom in on the 
 sun/moon until they are large enough to show their true scale.  (The sun and 
 moon are shown at a certain minimum size, so they are out of proportion on   
 large scale star maps.)  You might have to adjust the time setting a few     
 minutes by trial and error.  Try to show the moon just before and just after 
 it passes the sun.  By how far does it miss the sun each time?  Can you tell 
 when an eclipse will occur?                                                  
                                                                              
 --How much does the moon change size during the month?  Why does it change   
 size?  (It doesn't have a perfectly circular orbit.)  In the [Mm, Modify     
 Configuration] option set one of the eyepiece fields to 0.5 degree.  Plot a  
 series of moon images a day or two apart for a month overall.  Recenter the  
 map on one of them.  Change the map scale [Dm, F4, F6, 1 degree = 8 inches]  
 to make the narrow dimension of the 8 x 10 inch printout equal 1 degree.  Put
 the cursor near the center of the moon's disk and jump to the exact center   
 [Dm, <SpBar>, <Enter>, F2].  Place the 1/2 degree target on top of the moon  
 image for comparison.  Print it out.  Repeat for each of the moon images in  
 the month.  When is the moon largest?  Is there a pattern?  Does the size of 
 the moon's disk depend on the phase of the moon?  (No)  Repeat for a         
 different month to see if the pattern is the same.  (The time the moon is    
 closest to the earth is called Perigee.  The time it is farthest from the    
 earth is called Apogee.  DS3D does not print out times of Perigee and Apogee 
 directly, but it shows up in the moon images.  If you took pictures of the   
 moon at different times of the month with a telephoto lens you would see     
 variation in its size as predicted by DS3D.                                  
                                                                              
 --etc., etc., etc.  (If you find innovative ways to use DS3D or Planet       
 Tracker, I would like to hear about it.)                                     
                                                                              
                                                                              
 ==================== >> OVERVIEW FOR ACTIVE OBSERVERS << ====================
                                                                              
 I know who you are!  You are the ones who keep Willmann-Bell and Sky         
 Publishing Corp. in business.  Your copies of Burnham's and Atlas 2000.0 are 
 well worn, and the only reason your Uranometria isn't falling apart is it is 
 nicely bound and you treat it with respect.  Your RASC handbook survives     
 because it only has to last a for a year at a time.  You plan your vacations 
 around the phase of the moon and you consider a sunny day with high cirrus to
 be lousy weather.                                                            
                                                                              
 I realize you probably own one or more planetarium programs already, but I   
 think you will find DS3D to be a little different.  DS3D was designed with   
 you in mind, because I really wrote it for myself.  I didn't sit down and    
 write DS3D.  It grew.  It has very little in the way of frills.  If I spend  
 time implementing a feature there has to be a payoff in functionality.       
                                                                              
 Allow me to illustrate with a star party preparation scenario.               
                                                                              
 You sit down a day or two in advance of new moon weekend, choose this month's
 star party site from your site list, set the date for the star party night,  
 and bring up the Default Map.  You have modified the configuation to plot the
 planets automatically.  You subscribe to Comet Watch or CRAS, or someone in  
 your club gets circulars from the IAU directly, so your comet files are kept 
 up to date.  You scan for all comets brighter than 13th magnitude and add    
 them to the chart.  Perhaps you even scan the asteroid list for a few you    
 have been following.  A nova was recently discovered, but its position was   
 reported in 1950.0 coordinates.  (DS3D maps are all in 2000.0 coordinates.)  
 No problem.  You enter the coordinates, label them as having a 1950 equinox  
 date and let the program do the conversions and pinpoint the object on the   
 map [Dm, F7, F4].  Now you print out the Default Map.  This gives you an     
 overview of the whole night's territory.                                     
                                                                              
 (The all-night Default Map is my bid for the single most useful star party   
 planning tool.  You have the absolute limits with the sunset and sunrise     
 horizons, and the more practical limits set for the astronomical twilight.   
 The map is a true Mercator projection (see [Mm, Extended Help, Mapping       
 Basics]) to keep shapes recognizable over the whole map, even though there is
 area distortion.)                                                            
                                                                              
 Now you zoom to each comet that is well positioned, add stars to an          
 appropriate magnitude level, add the deep sky objects in the region that     
 might be mistaken for the comet, if the comet turns out to be a turkey, and  
 print out a finder chart for each one.                                       
                                                                              
 You go out to [Mm, Begin New Chart Stack] and return to the Default Map with 
 a clean slate.  Now you turn your attention to the deep sky objects on your  
 agenda.  (Let's say you are working on the Herschel list.)  A few months ago 
 you plotted out the whole Herschel list and created a category for your own  
 use called "Project."  You dumped the list into the category and you have    
 been removing the objects from that category as you have logged them and any 
 that were particularly impressive you added to another category you called   
 "Fine Fuzzies."  The "Project" category contains your current target list, so
 you display the whole category on the Default Map.  The ones that fall within
 good areas of the sky you zoom in on and make roughly constellation-sized    
 finder maps.  You label the target objects (thus adding them to the current  
 observing list), then add the objects from the database at large to put your 
 target objects in context.  If a label gets overwritten by an object you hit 
 the <Spbar>, move the cursor near the object, jump to it with [Dm, <Enter>,  
 F2], and move the label to a better location where it will not interfere with
 stars you may need for star hopping.  After each map you exit to the Main    
 Menu, select [Mm, Observing List], save the list with a name, for future     
 reference, and print it out.  The printed observing list shows the object    
 name with all the catalog information, and (optionally) a rise/set time line,
 and any previous notes you entered.                                          
                                                                              
 A couple of galaxies you saw before impressed you and you decide to do       
 sketches of them at the eyepiece.  You seek each object by its Messier, NGC, 
 or IC number with [Dm, F7, F5], and zoom into a Hubble Guide Star Catalog    
 (GSC) map [Dm, <SpBar>, <Enter>, F5,...].  The object shows up in the field, 
 drawn with its correct size and orientation.  For your present purposes you  
 don't want the object in the field, so you delete it.  You drop in an        
 appropriate eyepiece field of view circle, (high, medium, low, or finder     
 power) you filter the GSC map to limit it to stars of 13th magnitude or      
 brighter, and you have your sketch area ready to draw the galaxy without     
 having to plot all the field stars first.                                    
                                                                              
 You collect your maps together, staple each one to the corresponding         
 observing list and put the charts into your RubberMaid storage clipboard     
 (...hot new find for me!  Maybe you knew about them all along...) along with 
 your Night Sky planisphere and L.E.D. flashlight.  You have entered the age  
 of "Clipboard Astronomy."  You take your book bag along on the star party,   
 but it sits in the back of the van most of the night as a reference library  
 in case you happen on something you didn't expect.  You sit on your stool at 
 the eyepiece with your clipboard in hand equipped for a whole night's        
 observing.  You take your notes, do sketches of interesting star fields or   
 star-hopping paths, cross off GSC stars that aren't really there (...it's a  
 crude database, really, but boy is it deep!) and don't have to worry about   
 messing up your expensive reference books.                                   
                                                                              
 When you return home, you bring up the saved observing lists one at a time   
 and add your notes [Mm, Observing List, Browse, ...].  You delete the lists  
 to keep from cluttering up the directory.  (The notes go into a single User  
 Log, which is keyed to the main database.  The observing lists are really    
 just pointers into the User Log, so they aren't needed any more.)  You delete
 the observed items from "Project" and add a few to "Fine Fuzzies," and you're
 done.  Whenever you bring one of those objects up on the screen again, your  
 observing notes will be right there with the original catalog data.          
                                                                              
 (This scenario has variations, of course.  There is the laptop version, the  
 LX-200 user version, the public star party version, etc.  There is even the  
 serious comet hunter version.  (DS3D will help you do comet recovery serches 
 by outlining the search region for a returning comet that may be advanced or 
 delayed in its orbit.)  ... Then of course there is your version.  I don't   
 really know you after all.  Each of you will find your own innovative ways to
 use this flexible observer's tool.  Let me know when you do.)                
                                                                              
                                                                              
 ========================= >> THE HISTORY OF DS3D << =========================
                                                                              
 DS3D was not written all at once.  Nor was it originally written with the    
 software market in mind.  Its roots trace back to the mid 1970's when I wrote
 star mapping routines on a time-share minicomputer and pen plotter to produce
 my planisphere, The Night Sky, and a now out-of-print set of cards entitled  
 Deep Space 3-D(!).                                                           
                                                                              
 The first micro-computer version was written for the TRS-80 Model I.  A star 
 map took a half hour to compute and another 15 minutes (with a separate      
 program) to dump to a printer.  It had no screen graphics.  I used it to     
 generate comet finder charts for the Pomona Valley Amateur Astronomers, and  
 worksheets for my astronomy classes and teacher workshops.  (I still do      
 teacher workshops, by the way, if your school district might be interested.) 
 The first release of the program as a software product had to wait until a   
 fast enough PC came along, so star maps could be generated within the        
 attention span of the general public.                                        
                                                                              
 I feel it is wrong to characterize DS3D as a "Planetarium Program".  It is   
 not a "Video Star Show".  Version 4 gives very nice screen displays, but if  
 you stop there you are missing the point.  The video aspect of the program   
 was non-existent at first and has always been a secondary consideration.     
 Even now, you will notice, the map scale that is given is based on the 8"x10"
 printout dimensions, and labels for the NGC objects, when the object is not  
 selected, are simply little rectangles to indicate the size and location of  
 the names as they would appear on the printouts.  Video graphics plays the   
 same role in DS3D, as it does in desktop publishing: its primary role is to  
 allow interactive layout for customizing the printed output.  DS3D is        
 "Desktop Cartography"!  The production of printed maps is still its #1       
 strength -- DS3D produces the best printed star maps in the personal         
 microcomputer world.  (Read [Mm, Extended Help, Mapping Basics] if you think 
 this claim is exaggerated.)                                                  
                                                                              
 Some of you who have been on board since the early releases may wonder why   
 certain features have been prioritized as they have, and why they have been  
 so long in coming.  The pace of development relates to the fact that I am a  
 teacher, so most of my programming comes during vacation spurts.)  As for    
 priorities, comets were the first item because they have always been         
 difficult to observe without heavy computational support.  They are no harder
 to see than galaxies of the same magnitude, but they are harder to locate    
 because they move.                                                           
                                                                              
 The NGC objects were longer in coming.  I had access to various NGC databases
 for several years, but they always seemed so static--why bother, when there  
 are such good atlases available?  Furthermore, it was not clear to me at     
 first how best to handle all the clutter.  On-screen identification with a   
 cursor is one thing, but printed galaxies with printed labels was a nightmare
 to contemplate.  Once I had the selection and labeling process clearly       
 outlined in my mind my motivation increased, but time was still a problem.   
 To speed things along I entered into a cooperative arrangement with a very   
 talented former student of mine, Jim Liebgott, who undertook implementing the
 features related to deep sky objects.  Jim's contributions also include      
 improving the low-level sophistication of various parts of the program.  I am
 an astronomer who learned to program.  Jim is an excellent programmer who has
 learned some astronomy along the way.                                        
                                                                              
 Version 3.0 represented a qualitative breakthrough in the utility of DS3D as 
 an observer's tool.  Instead of just filling in the gaps where other         
 resources were weakest, it became a true general purpose observers' resource 
 package.  It brought together the functions of an almanac, an atlas, a       
 catalogue, a source of descriptive information, and an observing log.  All of
 that information was accessible at a glance for everything from "Match-the-  
 sky" constellation charts through detail rivaling Uranometria.               
                                                                              
 Version 4 is another equally big step forward.  One immediate difference     
 former users will notice is the "map stack" concept for specifying and       
 modifying maps.  Rather than have to select a constellation or specify       
 coordinates blindly, a single key-stroke puts you in a default map of the    
 whole sky for the current night, all night long.  "What's Up" for the current
 night is automatically pre-computed, and is re-run for any change in the     
 observing site, date, or time.  From the default map you can repeatedly      
 frame, zoom, recenter, change map specifications, add overlays and objects,  
 compute and display orbits, ... all interactively until you get exactly what 
 you want.  (The trade-off is slower performance on older computers, but math 
 co-processors will work wonders for this kind of computing, and they are     
 getting cheaper, as are faster motherboards!)  Each successive "map          
 definition" is stored on a stack, so you can retrace your steps to previous  
 maps.                                                                        
                                                                              
 Other major additions in Ver 4 include full VGA color coding by spectral     
 type, Hubble Guide Star Catalog support with color coding by object category,
 output to Postscript files and devices, a telescope pointing driver for the  
 Meade "Smart-Drive," used on their LX-200 and other telescopes, a Real Time  
 Mode for use on laptops in the field, fully developed planet display for     
 orbit views and finder charts over any range of dates, asteroid elements and 
 computations, the ability to add user-defined objects placed at user-        
 specified coordinates (with conversion from input coordinates of any         
 Equinox), new, more accurate algorithms for the sun, moon, and planets,      
 graphical indication of the phase, size, and orientation of the moon, size   
 and orientation of galaxies and other deep sky objects, user defined eyepiece
 fields, finder fields, and Telrad targets placed at any cursor position, 3-D 
 in full color on screen, object sorting and an improved editor for the       
 observer's log, an expandable observing site list, a search function for     
 Messier, NGC, and IC catalog objects, an expanded "Almanac" feature with all 
 moon phase dates and times for the current year, coordinate grids in various 
 formats for equatorial, ecliptic, galactic, and horizon coordinates, constant
 read-out for cursor position and angular distance measurement, automated     
 specification for a variety of special purpose maps, and more.               
                                                                              
 A Postscript driver, called GoScript, is included with the registered version
 of Ver. 4 at no additional charge.  GoScript can print Postscript files to   
 nearly any printer at the highest resolution available.  This is our answer  
 to those of you who have ink jets or other previously unsupported printers.  
 The GoScript dot matrix drivers are so far superior to our own, we have      
 discontinued our earlier low-resolution direct dot matrix support.  Direct HP
 Laserjet support has been continued, although GoScript can also be used for  
 output to the Laserjet.                                                      
                                                                              
 The newest release of GoScript, GS32.EXE, is the one distributed with DS3D.  
 It runs much cleaner than the older GS.EXE (in terms of potential memory     
 usage conflicts), it has 25 drivers built into it, and it can also be called 
 directly from DS3D, whereas the older version could not.  The tradeoff is it 
 assumes at least a 386 computer with at least one megabyte of extended       
 memory. If you are a registered user of DS3D Ver 4 and do not have a 386     
 computer and would like to try the older version, send $5 with a description 
 of your system configuration and we will send you the older version.         
                                                                              
 GoScript is not a shareware product and may not be passed along to friends   
 with the DS3D archive files.  Please respect the copyright and property      
 rights of LaserGo, Inc.                                                      
                                                                              
                                                                              
 ============================ >> MAPPING BASICS << ===========================
                                                                              
 The simplest way to project the sky onto a flat map is to plot a rectangular 
 graph of declination vs. right ascension with equal spacings in both axes.   
 This system is commonly mis-labeled a "Mercator" projection.  Plotting       
 declination vs. right ascension is easy, and it is fast, since it involves no
 computations, but the results are truly awful.  You might be interested to   
 know that the wrap-around full sky maps used in almost all of the "major"    
 astronomy software packages for the PC do exactly that!                      
                                                                              
 Nobody maps the earth with a straight latitude vs. longitude graph.  If a map
 of the earth were plotted this way anyone who stayed awake through 5th grade 
 would immediately recognize something was very wrong.  Things would look     
 reasonably good near the equator, but countries from the mid latitudes to the
 poles would be terribly distorted.  Apparently star mapping programs get away
 with this kind of thing because the stars are less familiar to most people   
 than the shapes of the continents on earth.                                  
                                                                              
 Every flat map of a spherical surface involves distortion, but cartographers 
 long ago learned how to work around distortion in creative ways.  The        
 familiar maps of the earth that hang in most school rooms use what is called 
 the Mercator projection, invented by Gerhard Kremer in the 16th century.  It 
 was the invention of this map projection that made long distance navigation  
 possible.  Mercator maps are not simple latitude vs. longitude plots.  Look  
 for a Mercator map of the earth in an atlas and notice that the spacing of   
 the horizontal lines increases in a regular way as you move away from the    
 equator.  The original objective was to design a map where a straight line on
 the map represented a constant compass bearing on the globe.  Navigating     
 along such a line may not always be the most efficient course, but it will   
 always get you there!                                                        
                                                                              
 The Mercator projection has another nice property, which is more relevant to 
 our purposes in mapping the sky: angles between short line segments on the   
 sphere are preserved on the map.  Thus shapes are well preserved.  Alaska and
 Greenland may look too big on a Mercator map, but they have the right shape, 
 and if you cut out a small section anywhere on the map, you would not notice 
 the distortion.  Flight maps to this day use the Mercator projection for     
 these reasons.  The shape of the cup of the Little Dipper on a Mercator      
 projection star map looks right, apart from size distortion.  A map with this
 property is called a conformal map.  Since shapes in the sky are the easiest 
 way for amateur astronomers to find their way around, having maps that       
 preserve shapes is important.                                                
                                                                              
 Another conformal map is the Stereographic projection, invented even earlier,
 by Hipparchus, who lived in the 2nd century B.C.!  The Stereographic         
 projection is a polar projection, which, similar to the Mercator projection, 
 has radial spacing that increases as you get farther from the center.  Again,
 angles on the sphere are preserved on the map, so shapes are well            
 represented.  The Stereographic and Mercator projections are the bread and   
 butter projections available in DS3D because of their conformal properties.  
                                                                              
 There are other issues besides the choice of a projection.  A Mercator       
 projection is easy to center on the equator and the Stereographic projection 
 is easy to center on the poles, but what if you want to look at some other   
 part of the sky?  Are other areas of the sky doomed to less accurate         
 representation?  NO!  Any point on the sphere can be made to be the center of
 the projection.  (For small scale maps it doesn't even matter what projection
 you use, as long as the center of projection is the center of the map.)  In  
 DS3D every map in every part of the sky is computed so that the center of the
 map is the center of the projection.  This takes some heavy computation, so  
 DS3D is a little slower than some of the flashier programs available, but the
 results are worth waiting a few extra seconds.  If you don't like the wait,  
 it's time to move up to a math co-processor.                                 
                                                                              
 The standard practice among star atlas publishers is to map the sky in       
 equatorial coordinates.  For most purposes these are the coordinates you will
 want to use for finding and tracking objects in the sky because it is based  
 on the rotation of the earth.  The rotation of the earth defines the poles   
 and the equator.  Where an object is in equatorial coordinates determines    
 when and whether it will rise and set for observers at a particular latitude.
 If we were printing a star atlas it would be most economical to limit our    
 attention to the most popular coordinate system.  On the other hand, this is 
 a computer, not a printing press.  You should be able to print out maps in   
 any coordinate system you want; and some of the other coordinate systems are 
 quite useful!                                                                
                                                                              
 DS3D gives equal access to four coordinate systems:  Equatorial, Ecliptic (or
 Zodiac), Galactic (or Milky Way), and Horizon coordinates.  You can plot maps
 centered in any part of the sky in any of these projections.  Furthermore,   
 you can lay down any combination of coordinate grids in any of these four    
 coordinate systems on any map.  (For instance, if you were interested in     
 following the motions of the planets you could lay down an ecliptic          
 coordinate grid, of either the whole sky or just the Zodiac region, on a map 
 plotted in equatorial coordinates.)  Coodinate Systems and Grid Lines are    
 discussed in detail elsewhere in these notes.  Each system is useful for its 
 own purposes.  DS3D give you the flexibility to create whatever maps serve   
 your needs or interests.                                                     
                                                                              
 DS3D is not a planetarium program; it is desktop cartography!                
                                                                              
                                                                              
                                                                              
 ======================= >> HARDWARE CONSIDERATIONS << =======================
                                                                              
 DS3D runs entirely in conventional 640K memory.  Actual memory usage by DS3D 
 is under 500K, leaving some flexibility for you to manage drivers and any    
 resident programs.  If memory limit problems do arise, you most likely have  
 too many other programs or drivers competing for conventional memory.  Try   
 loading DOS and other routines into high memory or remove memory-resident    
 programs.  The GoScript Postscript support utility (supplied with registered 
 versions only) will use extended memory to the extent available or swap its  
 workspace back and forth to hard disk if necessary.  Relying on hard disk    
 space rather than extended memory will make GoScript run much more slowly.   
 At least one Megabyte of extended memory is recommended.                     
                                                                              
 The HP Laserjet printer is supported directly by DS3D.  All other printers   
 are supported through Postscript.  The code is sent directly to Postscript   
 printers or to a file to be interpreted by GoScript.  Postscript output files
 are automatically numbered sequentially for ease of use.                     
                                                                              
 A math co-processor is optional but highly recommended.  Older machines      
 without a math co-processor will require much patience!  DS3D has always     
 assumed the least common denominator in hardware.  In recent years the least 
 common denominator has gone up, and we would be lost in the backwaters if we 
 did not take advantage of the increased performance level of today's         
 computers.  If you must run DS3D on a slow machine you can set the default   
 magnitude for whole-sky maps as low as possible, and turn off as many default
 features as possible.  You can cut off the plotting of stars with the <Esc>  
 key before they are all displayed and go to the menus to specify the map you 
 want with less graphical overhead.  Once the desired map has been framed and 
 centered you can add stars and other features.                               
                                                                              
                                                                              
 =============================== >> STARTUP << ===============================
                                                                              
 If you have not yet installed DS3D here is an overview.  DS3D is distributed 
 in three files called DS1of3.EXE, DS2of3.EXE, and DS3of3.EXE.  These are     
 compressed, self-extracting archive files that contain the actual program and
 related files.  Make a clean DOS directory and copy the compressed files to  
 it.  Expand each file by typing DS1of3, then DS2of3, then DS3of3.  Now type  
 INSTALL BBS to create the appropriate subdirectories and distribute the files
 to their proper locations.  (This is one of two installation methods.  Type  
 INSTALL with no parameters if you want to read about the other method.)      
                                                                              
 When you start DS3D for the first time, you are led through the most         
 essential configuration options.  You can alter your choices and modify other
 settings at any time by selecting [Mm, Modify Configuration].                
                                                                              
                                >> Video Mode <<                              
                                                                              
 The first item on the configuration agenda is to specify the type of video   
 card in your machine.  The software will attempt to detect which card is     
 present.  Under normal conditions you should be able to accept the default   
 selection.  If you have more than one video card installed or know that the  
 program is not detecting your card properly, enter the correct response.     
                                                                              
                               >> Directories <<                              
                                                                              
 INSTALL.BAT stores your main program files in a base directory of your       
 choosing.  (We will refer to the base directory as \DS3D for the discussion  
 here to make things more concrete.)  Data files that remain unaltered are    
 stored in \DS3D\DSDATA, and files created or altered by the program are put  
 in \DS3D\DSFILES.  If you used INSTALL.BAT to set up your directories you can
 simply accept the default settings.                                          
                                                                              
 You may arrange your directories differently, as long as you keep the file   
 groups together.  (For instance, you can put everything into one big         
 directory, if you prefer.  If you ever encounter "File Not Found" errors and 
 can't figure out what is misplaced, putting everything in one place may be a 
 satisfactory stop-gap measure.  If two people use DS3D on the same computer  
 and want to keep the output files separate, you might install two copies of  
 the program on different directories but allow them to access the same DSDATA
 directory to save space, especially if you have added the 250,000 star       
 extended database.)  Indicate any changes in the Directories section of the  
 Modify Configuration menu so DS3D can find the files it needs.               
                                                                              
 DS3D will check to make sure it can find all the critical files.  It will not
 continue if critical files are missing or misplaced.  When users have        
 difficulties running the program after reorganizing their hard drives, this  
 is the most common reason.  Running the DIRECTORIES configuration option will
 point to the files that are causing the problem.                             
                                                                              
                           >> Registration Status <<                          
                                                                              
 If the program is unregistered, this option allows you to imprint your       
 registration name and number.  If you want to testdrive the program in       
 unregistered mode, type <Esc> to bypass the question.  Type your REGISTERED  
 USER NAME and REGISTRATION NUMBER exactly as given on your registration slip.
 The number is an encryption of the name, so they have to match for the       
 registration to be considered valid.  (If there is a misspelling of your name
 on the registration slip, use the name as shown, temporarily, and request a  
 new number.)                                                                 
                                                                              
 Keep your slip containing your REGISTERED USER NAME and REGISTRATION NUMBER  
 for future reference.  If the file DSCONFIG.DSS is ever damaged or lost you  
 will have to go through the imprinting process again.                        
                                                                              
                                                                              
 ============================== >> PRINTOUTS << ==============================
                                                                              
 [Dm, F10, ...]                                                               
 DS3D supports printouts directly to HP Laserjet and Postscript printers.  It 
 will also direct either kind of output to a file.  File names for map files  
 have a shortened format, so that up to a two digit number can be appended to 
 the name prior to the extension to allow sequences of maps to be printed     
 efficiently.  For instance, if you name a Postscript file MYMAP with the     
 number 1, the name of the file will become MYMAP1.EPS.  The next file will be
 named MYMAP2.EPS, unless you intervene and change either the name or number  
 part.                                                                        
                                                                              
                                 >> GoScript <<                               
                                                                              
 If you have something other than an HP Laserjet or Postscript-compatible     
 printer, you can still print out maps.  We have arranged to include GoScript 
 with the registered version of DS3D.  GoScript is a Postscript interpreter   
 that supports a wide range of non-Postscript printers, including 9-pin and 24
 pin dot matrix printers and inkjet printers.  (GoScript is a registered      
 trademark of LaserGo, Inc.)  If you have the shareware version of DS3D you   
 may use either your own copy of GoScript or obtain a different Postscript    
 interpreter.  (Emulaser is a similar product, but we tried both and like     
 GoScript much better for our purposes.)                                      
                                                                              
 GoScript is not a shareware product and may not be passed along to friends   
 with the DS3D archive files.  Please respect the copyright and property      
 rights of LaserGo, Inc.                                                      
                                                                              
 If you have registered DS3D and want to send Postscript output to a non-     
 Postscript printer, enter [Mm, Modify Configuration, Printer].  Choose the   
 "P" option for Postscript and the "F" option for file output.  When you print
 out your output will go to a Postscript file.  If your system is a 386 or    
 better with at least one Megabyte of extended memory available DS3D can then 
 invoke GoScript immediately and send the file to the printer.  If you do not 
 have a 386 with extended memory available, a different version of GoScript   
 must be obtained and invoked manually once you have exited DS3D.  (Send $5   
 for a copy of the older version of GoScript.)  You can produce a whole series
 of sequentially numbered files in DS3D, then exit and print these to the     
 printer.                                                                     
                                                                              
 If you create a Postscript file called PSMAP1.EPS and want to send it to a   
 printer from DOS, exit to DOS and type:  GS32 PSMAP1.EPS.  Type  GS32 /P?    
 for a list of the internal device drivers.  Type  GS32 /?  for a list of     
 other parameters.  (If you obtain the older version of GoScript, type GS     
 instead of GS32.)                                                            
                                                                              
                                                                              
 ========================= >> PROGRAM REGISTRATION << ========================
                                                                              
 Registered users must imprint their REGISTERED USER NAME on the title frame  
 of the program.  Simply type your REGISTERED USER NAME and corresponding     
 REGISTRATION NUMBER at the opening configuration or in [Mm, Modify           
 Configuration].  Programs imprinted with the user's name are able to access  
 all star files (initially about 19,000 stars through file SST06, expandable  
 to about 250,000 stars through file SST77), the entire Saguaro Database of   
 non-stellar objects, which includes the NGC catalog (non-existent objects    
 deleted), and many objects from the IC, UGC, and other catalogs, and access  
 to the Hubble Guide Star Catalog Version 1.1 distributed by the Astronomical 
 Society of the Pacific on CD ROM.  All other functions of the program work in
 both registered and unregistered form.                                       
                                                                              
 A folding 3-D stereo viewer and the GoScript utility for printing Postscript 
 files to non-Postscript printers are also included with registration.        
 To register, print out an Order Form from [Mm, Catalog & Order Form] and send
 payment with your order in US Dollars drawn on a US bank.  We cannot accept  
 credit cards. When you register you will be sent the latest version of DS3D, 
 a stereo viewer, star files SST02-SST06, and a REGISTRATION NUMBER.          
                                                                              
                                                                              
 ======================== >> SHARING DEEP SPACE 3-D << =======================
                                                                              
 Shareware is not public domain software.  It is copyrighted software that    
 relies on satisfied users to be a distribution network.  Whether you register
 or not, if you like DS3D, share it!  You are our best advertisement.  If you 
 use a BBS, please upload a shareware copy.  We want to get the word out that 
 Version 4 is here.                                                           
                                                                              
 When you share DS3D with friends or colleagues, please pass along only the   
 original archived files.  (Look in the SHARE subdirectory.)  This ensures    
 that all needed files stay together.  We want your friends to have not only  
 the working program, but the ability to share it further.  The archived files
 are needed to transmit all the files efficiently and cleanly.  Do not share  
 your registration number or the file DSCONFIG.DSS, where your registration   
 name and number reside.                                                      
                                                                              
 If you are a registered user of Ver 4 you will have received a copy of       
 GoScript, by special arrangement with LaserGo Inc.  GoScript is not shareware
 and copies should not be given away.                                         
                                                                              
                                                                              
 ================== >> USING AND ALTERING DEFAULT VALUES << ==================
                                                                              
 One way to make a program usable by both beginners and experts is to allow   
 lots of choices for the experts, even regarding picky details, but to suggest
 an answer to every question that at least makes sense.  A "default" is       
 computer jargon for those pre-selected answers provided by the program.  DS3D
 has defaults for just about everything!  This makes it easy to explore areas 
 you may not understand very well at first.  If you come to a question you    
 don't care about or don't understand, just choose the default and keep going.
 The more you learn about astronomy, and the more you become familiar with    
 DS3D, the more you will appreciate having control over all the details.      
                                                                              
 To choose a default answer, simply type the <Enter> key.  You will find you  
 can go through almost the entire program simply hitting the <Enter> key, and 
 still get something of interest.  If you come to a whole page of questions   
 and you like the looks of all the default answers, simply jump to the bottom 
 of the page with the <PgDn> key and keep going.                              
                                                                              
 Most default values can be adjusted by the user.  Select [Mm, Modify         
 Configuration] and within it select the area of concern.  The values you     
 choose will become the new default values, but most settings can be          
 overridden at the time a star map is produced.                               
                                                                              
                                                                              
 ============================== >> DATA ENTRY << =============================
                                                                              
 There are several data entry formats.                                        
                                                                              
                              >> Scrolling Menu <<                            
                                                                              
 When you are presented with a menu having a highlighted scroll bar (eg. the  
 Main Menu), make your selection with the arrow keys, the first letter of the 
 desired option, or the <Arrow>, <PgUp>, <PgDn>, <Home>, or <End> keys.       
 Finalize your selection with the <Enter> key or escape with the <Esc> key.   
                                                                              
                                >> Input Box <<                               
                                                                              
 Most single character entries do not require the use of the <Enter> key.     
 Simply press the appropriate character key.  If you type an invalid character
 you will hear a beep and may try again.  Numbers and character strings       
 require you to type <Enter> to terminate the entry.  If you choose to accept 
 the default entry presented in the box, simply type <Enter>.                 
                                                                              
                                 >> Toggles <<                                
                                                                              
 A third form of data entry, used for selecting multiple items from a list, is
 a "toggle".  To make or undo a selection, type the <Space> bar.              
                                                                              
                                >> Data Pages <<                              
                                                                              
 For convenience, data entry is presented a page at a time.  You may use the  
 <Arrow> keys, <PgUp>, <PgDn>, <Home>, or <End> keys to move among the data   
 items.  You may not be allowed to leave a box until an entry of the proper   
 format is present.  To allow you to recover from accidental keystrokes, there
 is usually a question at the bottom of a page for confirmation.  If you are  
 satisfied with all the entries on a page you may jump directly to the bottom 
 of the page with the <PgDn> key.                                             
                                                                              
                             >> Editing an Entry <<                           
                                                                              
 When editing an existing entry, if the first key typed is a normal character,
 the entry will be erased under the assumption that you want to retype the    
 whole entry.  If you want to edit the entry without destroying what is       
 already there, make the first keystroke with a <Home>, <End>, or <Arrow> key.
 After destroying a few entries you will get used to it!                      
                                                                              
                                                                              
 ========================= >> OBSERVING SITE LIST << =========================
                                                                              
 Earlier versions of DS3D allowed up to two permanent observing site          
 descriptions and a third "floating" site description that could be re-defined
 on the fly.  Version 4 now allows the accumulation of as many observing site 
 descriptions as you want.  Each site is specified with a name, latitude,     
 longitude, altitude, two time zone names (for standard and daylight time),   
 and the hour offset of standard time from Greenwich.  For instance a site in 
 California would store time zone names PST and PDT and 8 hours offset from   
 Greenwich.  The choice of Standard Time, Daylight Saving Time, or UT can be  
 activated separately without changing the site information.                  
                                                                              
 As your site list grows you may want to prioritize the entries according to  
 how frequently you use the site.  A manual "sort" routine is provided as you 
 exit the Choose Observing Site option that allows you to arrange the sites on
 your list in any order you choose.  The distribution disks contain a small   
 sampling of popular astronomy sites and a collection of general region site  
 descriptions to help beginners get started quickly.  If you have data on     
 other popular star party sites, please write to me and I will compile a more 
 broadly based list for future releases.                                      
                                                                              
                                                                              
 =========================== >> THE DEFAULT MAP << ===========================
                                                                              
 Earlier versions of DS3D required you to go through several pages of options 
 to give the location, scale, projection, etc. for any map you produced.      
 Version 4 introduces a much more flexible system.  A Default Map covering the
 whole sky (except for the polar regions) is displayed with a single          
 keystroke: just type <Enter> when you first arrive at the Main Menu.         
                                                                              
 The Default Map is centered on the point along the equator 180 degrees around
 from the sun.  This point will be near overhead at midnight.  On the right,  
 the western horizon is shown for sunset and the end of astronomical twilight.
 On the left, the eastern horizon is shown for the beginning of astronomical  
 twilight and sunrise.  Thus, the Default Map shows the whole available sky   
 for observing at any time on a given night.                                  
                                                                              
 To plot a more localized map you can type <Spacebar> to bring up the cursor, 
 center the cursor on the point of interest, and hit <Enter>, <Enter>.  This  
 technique normally just recenters a map without changing its scale, but from 
 the Default Map (or the Circular Day-and-Time map or the Horizon-View map) it
 also zooms in to a pre-determined scale, which you can set in [Mm, Modify    
 Configuration].                                                              
                                                                              
 Alternatively you can zoom with [Dm, F3, F1] and choose any scale you wish   
 using the PgUp and PgDn keys.  Use the arrow keys to center the box and type 
 <Enter> to activate the zoom.                                                
                                                                              
 If you wish to specify a map using coordinates, or choosing a constellation  
 by name, or searching for a particular Messier, NGC or IC object you can use 
 [Dm, F4, F2].                                                                
                                                                              
 If you want to display a comet path or any other object, do it while you are 
 in the Default Map, then zoom to the area of interest once the exact location
 becomes known.                                                               
                                                                              
 If you try to display deep sky objects while in the Default Map (or any other
 all-sky map, for that matter, you may overwhelm yourself (and the memory).   
 Space has been allocated to display up to 1000 deep sky objects, but you can 
 fill up that space quickly if you display all galaxies down to 13th          
 magnitude, say, on a large scale map.  If you display objects for the whole  
 sky then zoom in and try to add more, you may encounter an out of memory     
 notice.  If you have been adding to an observing list (any object you label  
 goes into the observing list), exit to the Main Menu, select [Mm, Observing  
 List] and save your current list as a named file.  Then re-enter your current
 map and remove all deep sky objects [Dm, F8, F8, Y], giving you a chance to  
 start from scratch.  Removing all objects without saving your observing list 
 will erase it, so be careful.  Now you can go back and load your observing   
 list, enter the map again and continue.                                      
                                                                              
 In short, think of the Default Map as a summary map for a given date and at  
 the same time a launching pad for all the other mapping possibilities        
 available.                                                                   
                                                                              
                                                                              
 ============================ >> REAL TIME MODE << ===========================
                                                                              
 If you choose [Mm, Set Day and Time] you can determine a specific observing  
 time for later in the evening or later in the year.  If you take your        
 computer out observing with you, however, you will want it to keep up with   
 the current status of the sky throughout the night.  For this application,   
 activate RTM (Real Time Mode).  A green line indicating the current horizon  
 will show up on all maps that overlap the horizon.  The horizon line is not  
 animated, but the time will be updated and the horizon and all orbital       
 objects (planets, moon, comets, asteroids) will be updated every time the map
 is redrawn.  You can activate a redraw while in RTM by typeing the <Home>    
 key.                                                                         
                                                                              
 When you enter RTM you can give an offset in hours.  This allows you to      
 simulate nighttime situations earlier in the day.  For instance, if you are  
 using DS3D to drive an LX-200 telescope and want to work with it in the      
 daytime, you might want to simulate nighttime conditions to avoid having the 
 telescope tell you the object you are looking for is below the horizon.      
                                                                              
 Exit with [Mm, Turn off Real Time Mode].                                     
                                                                              
                                                                              
 ============================ >> THE MAP STACK << ============================
                                                                              
 DS3D maps in Version 4 are specified with a compact "Map Definition" that    
 saves all the information needed to regenerate a given map.  When you save a 
 map to disk with [Dm, F1, F1], what you are saving is a map definition.  When
 you are working with maps, zooming in and out, all the maps you generate     
 along the way are saved temporarily on a "map stack."  Every time you zoom in
 (with [Cursor, <Enter>, <Enter>] or [Dm, F3, F1] the previous map is "pushed"
 onto the stack.  When you zoom out, [Dm, F3, F2], the current map is         
 abandoned and the most recent map definition pushed onto the stack is        
 "popped" off the stack and reactivated.                                      
                                                                              
 An exception to the rule is when you recenter or zoom a GSC map.  You might  
 recenter or zoom a GSC map several times before you are satisfied with the   
 display.  The CD Rom access is rather slow and you probably would not want to
 retrace your steps through all the previous GSC maps to make your way back to
 the earlier conventional maps.  Therefore GSC maps are not stored on the     
 stack.  When you zoom out from a GSC map you will return to the most recent  
 non-GSC map that was pushed onto the stack.                                  
                                                                              
 If you want to dump the whole stack and start over, use [Mm, Begin New Chart 
 Stack].                                                                      
                                                                              
                                                                              
 ============================= >> SPECIAL MAPS << ============================
                                                                              
 [Dm, F2...]                                                                  
 You can specify maps of any description by choosing the centerpoint, scale,  
 projection, coordinate system, etc.  However, certain map formats are common 
 enough to merit a shortcut to their specification.  These have been grouped  
 under [Dm, F2] (Special Maps).                                               
                                                                              
                                                                              
                        >> Circular Day and Time Maps <<                      
                                                                              
 [Dm, F2, C]                                                                  
 Since the earth rotates, the sky changes constantly.  A circular star map    
 showing the whole sky needs to be keyed to a particular day and time.  What  
 is shown will be adequate for finding constellations over about a month at a 
 given hour, or over a few hours on a given night.                            
                                                                              
 For general purpose all-night use you will still want to obtain a "Star      
 Wheel," or planisphere, such as The Night Sky, listed in our catalog.  A     
 planisphere can be updated continuously throughout the night.  For a specific
 celestial event, or brief observing period, however, circular Day and Time   
 charts generated by DS3D will do very nicely.  They are ideal for passing out
 to a scout troop or school group for an evening's sky orientation.           
                                                                              
 The map projection used on the Circular Day and Time maps is a stereographic 
 projection.  The late George Lovi, who drafted the star chart "centerfolds"  
 in Sky and Telescope for years also used the stereographic projection.  He   
 pointed out that the distortion introduced by this projection actually       
 matches the perceived sky better than a distortion-free map!  This is because
 of something known as the "Moon Illusion."  The moon, when it is near the    
 horizon, appears much larger than when it is overhead.  This is strictly an  
 illusion.  When the moon is measured it is found to be exactly the same size 
 in either position.  Constellations near the horizon undergo the same        
 apparent enlargement to our eyes, mimicking the distortion of a stereographic
 map centered overhead.                                                       
                                                                              
                               >> Horizon Maps <<                             
                                                                              
 [Dm, F2, H]                                                                  
 The Horizon maps are actually just zoomed-in circular Day and Time maps      
 rotated according to the direction you specify.  The scale is larger and     
 using a horizon map can be less confusing to a novice since orienting the map
 is less of a problem.  This type of map is often an excellent format to      
 displaying planetary events or the location of comets near the horizon.  See 
 the discussion of Circular Day and Time Maps for more detailed information.  
                                                                              
                                                                              
                              >> Whole Sky Maps <<                            
                                                                              
 [Dm, F2, W, ...]                                                             
 The Whole Sky maps are true Mercator projection 360 degree views of the sky  
 centered along one of the primary great circles: the equator, the ecliptic,  
 the galactic equator, or the horizon.  For simplicity of terms, we have named
 these options Equatorial, Zodiac, Milky Way, and Horizon.                    
                                                                              
 Equatorial -- If you want a wrap-around view of the whole sky, similar to the
 default map, but without the double horizon lines, and possibly centered     
 about some other point on the equator, then [Dm, F2, W, E] will produce the  
 map you want.                                                                
                                                                              
 Zodiac (Ecliptic) -- The ecliptic is the path of the sun through the sky.    
 Since the solar system is roughly co-planar, the moon and planets appear to  
 travel within a narrow band close to the ecliptic called the Zodiac.  If you 
 are mapping the planets or other solar system phenomena, a chart oriented    
 along the ecliptic may best serve your needs.                                
                                                                              
 Milky Way (Galactic) -- The Milky Way forms a circle around the sky because  
 it is a disk, and we lie within the disk.  Our solar system is a tiny speck  
 about half-way out to one edge and slightly below the central plane.  When we
 look toward the center of the galaxy the Milky Way looks denser.  The center 
 is in the direction of the constellation Sagittarius.  On maps plotted in    
 galactic (Milky Way) coordinates, the plane of the galaxy is horizontal.     
 Zero degrees galactic longitude and latitude is looking directly into the    
 center of our galaxy.  Galactic maps are useful for studying distributions of
 star clusters and nebulae, and young blue stars which are concentrated along 
 the galactic disk.  Galaxies, on the other hand, are seldom found along the  
 Milky Way, since dust in the plane of our galaxy blocks the view of the      
 outside universe.  The distribution of globular clusters centers on one point
 in the Milky Way: a point in Sagittarius.  This is how it was first          
 determined that we are off-center.                                           
                                                                              
 Horizon -- Any horizon map depends on the time of observation, since our     
 horizon is tied to the rotating earth.  A 360 degree Mercator map centered on
 the horizon will probably be less useful than other formats: only the top    
 half of the map will be above the horizon!  This map was originally included 
 for completeness.  On the other hand you might find such a map useful for    
 selecting and zooming to areas of the sky with the correct orientation for a 
 particular day and time.  For instance you may want to produce a set of Ben  
 Meyer-style "Star Frames" for a particular evening.  If you do "Match the    
 Sky" charts in horizon coordinates the constellations will be shown with the 
 correct orientation.  Choose the Whole Sky Horizon map, center a particular  
 constellation, convert the resulting chart to a Match-the-Sky mode, zoom out,
 and repeat the process for each area of interest.                            
                                                                              
                                                                              
                            >> Pole-to-Pole Maps <<                           
                                                                              
 [Dm, F2, P ...]                                                              
 Pole-to-Pole Maps show the sky along a meridian strip.  The is similar to the
 format of Norton's Star Atlas.  This is a fairly good way to present the sky 
 on a season-by-season basis.                                                 
                                                                              
                                                                              
                            >> Match-the-Sky Maps <<                          
                                                                              
 [Dm, F2, M ...]                                                              
 Ben Mayer, a well known amateur astronomer in California, has popularized a  
 handy star-finding device made by bending a coat hanger into a rectangle and 
 covering it with transparent plastic wrap.  Stars are marked on the plastic  
 with white correction fluid (to be visible with a flashlight at night) in    
 such a way that they exactly match the sky when held a short distance in     
 front of the eyes.  These star finders are especially handy for showing      
 constellations to beginners.  The weak point of the system, until now, has   
 been knowing how to place the dots to match the sky.  DS3D solves the        
 problem.  Make a Match-the-Sky printout of the constellation of interest and 
 use it as a master for tracing onto the plastic wrap.  This can be a great   
 classroom project for teachers at any grade level.  Alternatively, you could 
 print transparencies directly with a laser printer or by Xeroxing.  You would
 still need to go over the dots of interest with white correction fluid to    
 make them visible at night.                                                  
                                                                              
 To make a Match-the-Sky Map you can either center a map on the area of       
 interest, then enter the Match-the-Sky option to re-scale it correctly, or   
 enter the Match-the-Sky option at the outset and select the constellation or 
 coordinate center point you wish.  The scale of Match-the-Sky Maps is        
 determined by a distance the map is to be held in front of the eyes.  The    
 projection used is Gnomonic, which gives an exact correspondence looking     
 through a plane surface at the spherical sky.                                
                                                                              
                                                                              
 =========================== >> CURSOR MOVEMENT << ===========================
                                                                              
 [Dm, arrow keys]                                                             
 When a star map is plotted you can bring up a cursor by hitting the space    
 bar.  (You can remove the cursor and return to the Display Menu by typing    
 <Esc>.)  Move the cursor with the arrow keys.  It will move slowly at first  
 and accelerate if the arrow key is held down.  (If you are using the arrow   
 keys on a number pad, remember to de-activate the NumLock key.)  If you type 
 the arrow keys without holding them down the cursor will move a single pixel 
 at a time.                                                                   
                                                                              
                                                                              
                           >> Angular Measurement <<                          
                                                                              
 [ Move cursor to Point A, type <SpBar>, move cursor to Point B... ]          
 When the cursor is active a box will be displayed and constantly updated     
 showing the sky coordinates at the cursor position.  The coordinate system   
 will match the coordinate system of the map: R.A. and Dec. for equatorial    
 maps, Ecliptic Latitude and Longitude for Zodiac maps, Galactic Latitude and 
 Longitude for Milky Way maps, and Altitude and Azimuth for Horizon maps.     
 Positions are to the nearest minute, for normal maps, and to the nearest     
 second for maps accessing the Hubble Guide Star Catalog.                     
                                                                              
 The cursor can also be used for measuring angular distances.  Say you have   
 observed a comet and sketched its tail on a star map.  To measure the length 
 of the tail, position the cursor where the head was seen, type the           
 <Spacebar>, to zero the "Diff." reading, then move to the location of the end
 of the tail.  "Diff." measures the angular distance along the shortest arc   
 connecting the two points accurate to the nearest minute or the pixel        
 resolution, whichever is coarser.  On Hubble Guide Star maps "Diff." measures
 to the nearest arcsecond.                                                    
                                                                              
                                                                              
 ====================== >> CURSOR ACTIVATED FEATURES << ======================
                                                                              
 Once you position the cursor and type <Enter> an array of position-related   
 features becomes available:                                                  
                                                                              
                                 >> Recenter <<                               
                                                                              
 [move cursor, <Enter>, <Enter>]                                              
 Typing <Enter> a second time will recenter the map at the cursor location.   
 The previous map will be pushed onto the mapstack and can be retreived by    
 "Unzooming" [Dm, F3, F2].  If the original map was the Default Map, a        
 Circular Day-and-Time map, or a Horizon map, recentering will also zoom to a 
 default zoom scale.  Initially the default zoom scale is 10 degrees per inch,
 but you can change it in [Mm, Modify Configuration].                         
                                                                              
                                >> Jump To... <<                              
                                                                              
 [Position the cursor near an object, <Enter>, F1 (or F2 or F3)]              
 If the cursor is within a half inch of an object you can cause it to jump to 
 the nearest object of whichever type you choose:  F1 for stars, F2 for the   
 sun, moon, planets, comets, or asteroids, or F3 for deep sky objects.  An    
 object added by specifying its coordinates might be either local or deep sky.
 (For instance it could be a nova, or the observed position of a comet or     
 even a satellite.)  For purposes of classification, individually added       
 objects are grouped with deep sky objects.                                   
                                                                              
                  >> Telrad Targets & Field of View Circles <<                
                                                                              
 [Center the cursor, Type <Enter>, F4...]                                     
 You can place a Telrad target, a Finder Field, or a High, Medium, or Low     
 Power Eyepiece Field at any cursor location by choosing the Targets option.  
 You can specify the angular sizes of each of the field of view circles in    
 [Mm, Modify Configuration].  Up to 10 targets or field of view circles can be
 placed on a map.                                                             
                                                                              
                       >> Zoom into Guide Star Catalog <<                     
                                                                              
 [Center the cursor, Type <Enter>, F5...]                                     
 The Hubble Guide Star Catalog (GSC) has approximately 18 million entries,    
 scanned by an automated process from photographic plates.  Most entries are  
 stars, but some are classified as galaxies, "blends", "non-stars," or        
 artifacts.  It would not be a satisfactory general purpose database.  There  
 is very little data about each star: basically position, brightness, and     
 tentative classification.  Its organization is optimized to show very small  
 areas of the sky in great detail.  One needs to keep in mind the original    
 purpose of the catalog: to assist in pointing the Hubble Space Telescope.    
 The goal was to catalog a few thousand stars per square degree so anywhere   
 the telescope was pointed there would be a few reference stars in its wider  
 field.  For that reason the magnitude cut-off is irregular.  In some parts of
 the sky stars are plotted to about 16th magnitude.  In denser regions of the 
 sky, particularly along the Milky Way, the magnitude is limited to 14th      
 magnitude or less.                                                           
                                                                              
 The GSC is excellent for plotting eyepiece-size fields of view.  Open star   
 clusters, in particular, are shown in spectacular detail.  Just about any    
 stars you can see in even large amateur-sized telescopes will be shown on a  
 GSC map.  One application we have already used heavily (during the           
 development stages of Version 4) is plotting field of view charts as a       
 background for sketching at the eyepiece.  Sketching is a great activity.  It
 helps you focus on subtle details and you wind up seeing much more than when 
 you are just casually viewing.  The first step in a good sketch is the       
 tedious part: drawing in the field stars to give the the sketch proportion   
 and scale.  With a GSC field of view chart, and a 1 degree, or so, field of  
 view circle centered on the location of your target object, the field stars  
 are already in place, so you can start right in with the object itself!  The 
 resulting sketch will be better proportioned and even a reliable indicator of
 the size of the object.  When observing a comet, for instance, the coma      
 diameter can be sketched reliably and measured later with the cursor by      
 comparing the sketch with the view on-screen.  It is possible to achieve     
 better accuracy this way than estimating the size directly at the eyepiece.  
                                                                              
                                                                              
                        >> Point LX-200 Telescope... <<                       
                                                                              
 [Center the cursor (or jump to the object of interest), <Enter>, F6]         
 If you are the owner of a Meade LX-200 (or other Meade telescope with a      
 "Smart Drive"), and have a laptop computer or a home observatory, you can    
 enhance your observing experience by letting DS3D point the telescope instead
 of working from the hand paddle directly.  You can locate your targets       
 graphically, rather than reading numbers in the dark, and you can enter your 
 observing notes directly in the field.                                       
                                                                              
 You will still need your hand paddle for aligning the telescope, but once it 
 is aligned, DS3D can send the coordinates of any cursor position.  You might 
 want to zoom in somewhat, so the accuracy of the coordinates will not be     
 limited by the low pixel resolution of the whole-sky views.                  
                                                                              
 To communicate with the telescope you will have to make your own data cable. 
 Instructions are given in the LX-200 manual.  The data cable is simply a 6-  
 strand telephone cable.  You can get the cable, the connectors, and the tool 
 for crimping them at any Radio Shack or other electronics supply store.  Be  
 sure to tell DS3D what COM port you are using by going into [Mm, Modify      
 Configuration].                                                              
                                                                              
 You will find that the screen of a laptop computer is a distrating light     
 source at night unless you cover it with red filter material.  Ask for       
 "Rubylith" at a drafting or art supply store.                                
                                                                              
                                                                              
 =========================== >> MAP ALTERATIONS << ===========================
                                                                              
 [Dm, F4...]                                                                  
 Early versions of DS3D required the user to specify the center position,     
 scale, magnitude limit, map projection, and various other parameters before  
 arriving at the first map.  Version 4 puts you into a map one keystroke past 
 the Main Menu.  The flexibility is still all there, but rather than pre-     
 determining all the settings, the initial maps are created with default      
 settings.  Centering and scaling can be done graphically, and [Dm, F4] allows
 you to modify the settings as you wish.  Since the intermediate stages in    
 producing a map are stored on the map stack, you can easily backtrack at any 
 point.                                                                       
                                                                              
                             >> Magnitude Limit <<                            
                                                                              
 [Dm, F4, F1]                                                                 
 From ancient times star brightness has been measured on a "magnitude" scale. 
 The brightest stars were considered 1st magnitude and the faintest stars     
 (visible with the naked eye) were ranked as 6th magnitude.  Modern astronomy 
 still uses this scale but extends it to larger numbers for fainter stars and 
 to zero and negative numbers for brighter objects.  Measured with photometers
 a few "1st magnitude" stars are measured at zero and slightly negative       
 magnitudes values.                                                           
                                                                              
 If you are doing whole-sky charts something around 4.5 would be a good       
 magnitude cut-off.  This is the cut-off I used for making the large scale    
 versions of The Night Sky.  You would have to go close to Mag 5 to get every 
 last star used in the constellation patterns.  Clutter is as much a          
 consideration as the limits of visibility.  Whole-sky maps are for general   
 orientation.  Only the brightest stars are needed in most cases.  As you zoom
 in you can add more stars as long as the chart remains readable.  [Mm, Modify
 Configuration] allows you to set separate default limits for whole-sky views,
 zoomed-in views, Guide Star maps, and deep sky objects.  Any of these can be 
 changed for individual maps: star magnitudes from the [Dm, F4, F1], and deep 
 sky objects during the selection process.                                    
                                                                              
 In [Mm, Modify Configuration, Telescope Parameters] you can evaluate your    
 telescopes according to the usual formulas.  With a 12 inch telescope, at    
 high power, under dark, clear skies, an experienced observer should be able  
 to see stars to about 15th magnitude.  Extended objects, such as galaxies,   
 are more difficult to see and have lower magnitude limits.  The predictions  
 should be taken with a grain of salt.  They are useful as a rough indicator, 
 but you should test your own practical limits with your own eyes, equipment, 
 and observing conditions and come to your own conclusions.                   
                                                                              
                                                                              
                        >> Coordinates of the Center <<                       
                                                                              
 [Dm, F4, F2,...]                                                             
 For most purposes you will want to set the center of a map graphically with  
 the cursor or the zoom box.  [Dm, F4, F2], however, gives you several other  
 options.  You can specify coordinates directly (in whatever coordinate system
 the map is using), automatically center on a constellation, or search for a  
 Messier, NGC or IC catalog deep sky object.                                  
                                                                              
                               >> Star Colors <<                              
                                                                              
 [Dm, F4, F3]                                                                 
 This option toggles between stars color-coded according to spectral type and 
 plain white stars.  The color option works properly only with VGA monitors.  
 EGA monitors will display color, but not the correct ones.  If the EGA color 
 selection doesn't bother you, you can leave it on, otherwise use it in       
 monochrome mode.  CGA, and Hercules displays should leave the color setting  
 turned off.                                                                  
                                                                              
 A star's color indicates its temperature.  Blue stars are the hottest.  They 
 are also the most massive and burn out fastest, so they are of necessity     
 young stars.  Bright blue stars dominate the spiral arms of the Milky Way,   
 where star formation is most active.                                         
                                                                              
                          >> Direct / Reversed Maps <<                        
                                                                              
 [Dm, F4, F4]                                                                 
 If your telescope has an optical system with an even number of reflections   
 (0 for straight-through finders and refractors or 2 for Newtonians), the     
 field of view will be rotated, but not reversed.  If your telescope has an   
 odd number of reflections (1 for right-angle finders and refractors with a   
 star diagonal, or 3 for Schmidt-Cassegrain), the field will be mirror imaged.
 (This is bad news for a finder scope!  Get a Telrad sight and use your right-
 angle finder only for fine centering.)  If you spend your telescope time     
 looking at mirror imaged fields, you have two options.  You can hold your map
 face down and show a red light through it, or you can print out reversed     
 maps.  Try it both ways.  If you sketch at the eyepiece you will definitely  
 want to make your Guide Star Catalog field of view charts reversed.          
                                                                              
                           >> North-Up / South-Up <<                          
                                                                              
 [Dm, F4, F5]                                                                 
 There is a strong tendency toward unconscious northern-hemisphere chauvinism 
 among northern-hemisphere astronomers.  I have tried to make DS3D free of    
 this bias as much as possible.  I am sure my Australian bretheren will find  
 places where I slip up; clue me in if you find such slip-ups.  Actually, I   
 want DS3D to be a useful tool for me when I go south!  South-up charts allow 
 southern astronomers to read their star maps without having to read the      
 printing upside down.                                                        
                                                                              
                                >> Map Scale <<                               
                                                                              
 [Dm, F4, F6]                                                                 
 This is another feature that will usually be handled graphically with the    
 zoom box, but there are occasions when you will want a particular measured   
 scale for your printouts.                                                    
                                                                              
 For example, a map printed with a Gnomonic projection can be made to exactly 
 overlay a photograph and match all the way across.  If you want to match a   
 photograph at some point, you may have to measure the scale and set it       
 directly.                                                                    
                                                                              
 I came up with a creative use of DS3D, using this feature, when I was        
 participating in Project SPICA, an astronomy mentor program for teachers at  
 the Harvard Center for Astrophysics.  Think of printed star maps as random   
 dot patterns representing the distribution of galaxies in the universe.      
 Two printouts set to slightly different scale can represent the state of the 
 expanding universe at the present and another time, say a billion years in   
 the past.  Print the maps on transparencies and overlay them.  You will see a
 spray pattern giving a dramatic graphical representation of the expansion of 
 the universe.  The apparent center of the expansion will shift if you shift  
 the overlays relative to each other.  Line up any dot on one sheet with the  
 corresponding dot on the other and it will appear to be the center of the    
 expanding universe!  To mimic a pair of charts 1 billion years apart in a 15 
 billion year old universe, set one chart to, say, 10 degrees per inch and the
 other to 15/14ths of that value: 150 degrees per 14 inches.  (Note that by   
 making the degrees and inches separate entries, you can usually avoid having 
 to divide the numbers out.)  The effect is startling!  You have to see it to 
 believe it.                                                                  
                                                                              
                              >> Map Projection <<                            
                                                                              
 [Dm, F4, F7...]                                                              
 Representing the spherical dome of the sky on a flat map means something has 
 got to give!  The question is what kind of distortion is least bothersome for
 a particular application.  Each projection offers a different trade-off.     
 Some projections distort shapes, others distort areas.  Others introduce more
 exotic distortions.  Generally speaking, for constellation recognition       
 preserving shapes is important.  Thus the collection of projections offered  
 in DS3D specializes in shape preserving projections of one kind or another.  
 (See [Mm, Extended Help, Mapping Basics] for more discussion of map          
 projections in general.)                                                     
                                                                              
 The Stereographic Projection should not be confused with stereo 3-D images.  
 (The possible confusion is particularly apparent in this program that        
 highlights stereo 3-D!)  Basically, to flatten out a rubber ball, the edges  
 must be stretched, causing a lengthening in the east-west direction.  The    
 Polar Equidistant Projection has just such a distortion.  The Stereographic  
 Projection compensates for the shape distortion by stretching the surface    
 radially so east-west and north-south distortions match at every point.  The 
 result is exaggeration of size far from the center, which is the price paid  
 for keeping the shapes correct.  ([Mm, extended Help, Special Maps] has      
 more discussion on this point.)  Overall, the Stereographic projection is one
 of the best projections for general purpose use, so it has been chosen as the
 original default projection for less than full sky views.  (You can alter    
 that choice, of course, in [Mm, Modify Configuration].)                      
                                                                              
 The POLAR EQUIDISTANT PROJECTION is the one typically used for planispheres. 
 It distorts shapes more than the stereographic projection, but it distorts   
 sizes less.  It is a reasonable compromise if less than half the sky is to be
 plotted.                                                                     
                                                                              
 The MERCATOR PROJECTION was designed for navigation and is discussed at      
 length in [Mm, Extended Help, Mapping Basics].  The Mercator projection has  
 "compensatory stretching" similar to the Stereographic map, so it also       
 preserves shapes at the expense of area distortion far from the center line. 
 Whereas the Stereographic projection is accurate at a point, the Mercator    
 projection is accurate along a line.  The Mercator Projection is a good      
 choice for wrap-around views of the sky.  It is used in the Default Map, the 
 Whole Sky 360 Degree View maps, and the Pole-to-Pole maps, accessible under  
 Special Maps [Dm, F2,...].  Two variations of the Mercator projection are    
 offered in DS3D:  N-S and E-W, depending on the nature of the material to be 
 mapped.                                                                      
                                                                              
 The GNOMONIC PROJECTION is the kind of a projection produced by a camera.    
 Cameras project the dome of the sky through a point onto a plane.  This is   
 called a Gnomonic projection.  People tend to believe photographic images are
 somehow more true-to-life than maps, but the Gnomonic projection has severe  
 shape and area distortion far from the center in a wide-field view.  I like  
 to use this projection when mapping comet orbits because this projection     
 preserves the conic sections.  If you wanted to create a map to overlay a    
 photograph the Gnomonic projection would also be the correct choice.  If you 
 were to paint dots on a window as you looked at the sky, you would have      
 Gnomonic projection map.  For this reason it is the projection used for the  
 MATCH-THE-SKY charts.                                                        
                                                                              
 Small portions of the sky can be mapped using any of these projections and   
 you would have a hard time telling the difference without overlaying one on  
 another.                                                                     
                                                                              
                                                                              
                            >> Coordinate System <<                           
                                                                              
 [Dm, F4, F8...]                                                              
 DS3D uses four basic coordinate systems corresponding to four significant    
 great circles on the sky:                                                    
                                                                              
 Equatorial (aligned with the equator, defined by the rotation of the earth)  
 Ecliptic (Zodiac / aligned with the earth's orbit around the sun)            
 Galactic (Milky Way / aligned with the plane of our galaxy)                  
 Horizon (aligned with the horizons and our sense of up and down)             
                                                                              
 Any map can be switched between coordinate systems while preserving the      
 center point and scale.  For whole sky views see the Special Maps section.   
                                                                              
 The horizon system is dependent on observer location and the day and time.   
 The others are not.  The Equatorial system is the one used for general       
 purpose star atlases, since it is tied to the rotation of the earth and hence
 the rotation of the sky as well.  The equatorial system makes sense only on  
 earth.  If we take a point of view from space it makes more sense to take our
 bearings from the plane of the solar system or the plane of the galaxy than  
 to worry about the rotational plane of a little planet down there somewhere! 
                                                                              
 Each system has its own purposes.  For use as a constellation finder the     
 horizon system shows what you see, if you are standing up, that is.  The     
 equatorial system is standard for star atlases that map the whole celestial  
 sphere for star-finding purposes independent of the local horizons.  The     
 Zodiac view is good on or off the earth for studying planetary motions or the
 motions of asteroids and comets.  Galactic coordinates are good for studying 
 star clusters, nebulae, and other things associated with our galaxy.  Even   
 Galactic coordinates seem provincial when we move out into the realm of the  
 galaxies.                                                                    
                                                                              
                       >> Horizontal / Vertical Format <<                     
                                                                              
 [Dm, F4, F9]                                                                 
 This option toggles between what is known in desktop publishing jargon as    
 "portrait" and "landscape" modes.  Both are proportioned to fit on an 8-1/2 x
 11 inch printout.  If you want different dimensions, use the cropping        
 feature.                                                                     
                                                                              
                                 >> Cropping <<                               
                                                                              
 [Dm, F4, F10...]                                                             
 The cropping feature allows you to size a printout for cut-and-paste         
 applications such as astronomy club news letters.  Simply specify the        
 dimensions.  Cropped maps continue to operate on the map stack like any      
 other.                                                                       
                                                                              
                                                                              
 =============================== >> OVERLAYS << ==============================
                                                                              
 [Dm, F5...]                                                                  
 Constellation lines, constellation names, and coordinate grid lines have been
 grouped under this general heading.                                          
                                                                              
                      >> Constellation Lines and Labels <<                    
                                                                              
 [Dm, F5, (F1 through F4)]                                                    
 [Dm, F5, F2] draws connect-the-dot-type constellation lines for all          
 constellations (except Mensa, which has no stars worth connecting!).  [Dm,   
 F5, F1] limits the selection to "Bright" constellations.  You can determine  
 which constellations you consider "Bright" in [Mm, Modify Configuration].  If
 you have already drawn the constellations, [Dm, F5, F1] will re-draw the map 
 with the more limited set.  Limiting the constellations displayed is a useful
 tool for teachers who do not want to overwhelm students at the outset.  It is
 also useful for beginners who want to avoid overwhelming themselves at the   
 outset!                                                                      
                                                                              
 [Dm, F5, F3] will add names, if the constellations are already drawn, or draw
 the lines and add the names otherwise.                                       
                                                                              
 [Dm, F5, F4] will add lines, if necessary, add the names, if necessary, and  
 set the cursor on the first name ready to be repositioned.  Use the arrow    
 keys to place the little rectangle (representing the printed version of the  
 name) where it will not interfere with the content of the chart.  Type       
 <Enter> to continue to the next name or <BkSpace> to cycle backward through  
 the list.  If the original location of the name is obscuring detail making   
 the placement of the name difficult, move the name away, type <Enter> to     
 complete the move and erase the original clutter, then type <BkSpace> to     
 return and place the name properly.  After the constellations are named you  
 can cycle back through the naming process to move the names as often as you  
 wish.                                                                        
                                                                              
 Any names you do not find helpful can be deleted with the <Del> key.  Names  
 cannot be easily recovered once deleted.  If you have deleted names you      
 wanted to keep or otherwise made a mess out of the naming procedure, type    
 [Dm, F8, F3] to remove all names, allowing a restart without having to redraw
 the map.  [Dm, F8, F2] will remove both names and constellation lines.       
                                                                              
 To cope with crowded conditions you may want to use the 3-letter             
 abbreviations of the names rather than full names.  Do this by typing the    
 <PgDn> key.  You can return to the full names by typing the <PgUp> key.      
 These keys affect all of the names.  They cannot be applied to the names     
 individually.                                                                
                                                                              
 Names with two words, like Canis Major or Triangulum Australe can be         
 represented either one above the other or end to end.  Use the <End> key to  
 string them end-to-end and the <Home> key to stack them one above the other. 
                                                                              
 If you want to show constellation lines for just one or a limited number of  
 constellations, name the constellations you want to keep, then type [Dm, F8, 
 F1] to delete the lines for the others.                                      
                                                                              
 It is a good idea to save labeling until last, after you have centered and   
 framed your final map and added any solar system or deep sky objects.  Naming
 is lost when you zoom or recenter a map.                                     
                                                                              
                          >> Coordinate Grid Lines <<                         
                                                                              
 [Dm, F5, (F5 or F6)]                                                         
 Grid lines at 10 degree or one hour intervals for any of the four coordinate 
 systems can be displayed on maps regardless of the coordinate system used for
 plotting the map.  Variations on the grid systems add to the flexibility.    
 These include:                                                               
                                                                              
 --Plotting the full coordinate system                                        
 --Marking only the equator (or other central circle)                         
 --Marking only the poles or the equator and poles                            
 --For the Ecliptic (Zodiac) grids, limiting the grid system to the 15 degrees
   either side of the ecliptic                                                
 --For the Horizon grids, limiting the grid system to the half of the sky     
   above the horizon at the time                                              
                                                                              
 Any combination of these options can be chosen for the default grid system in
 [Mm, Modify Configuration] and selected with the [Dm, F5, F5] keystroke      
 combination.  [Dm, F5, F6] allows you to modify the grid system for a single 
 map without reconfiguring.                                                   
                                                                              
 Note: The dashed lines forming the grids are spaced one degree on, one degree
 off, except for RA lines (which are five minutes on, five minutes off) and   
 the equator, which is solid.  You can use this fact to read coordinates to   
 one degree (or five minutes of RA) on printouts.                             
                                                                              
                                                                              
 ============================= >> SOLAR SYSTEM << ============================
                                                                              
 [Dm, F6...]                                                                  
 The term Solar System, as used here is a way of grouping all operations      
 related to the sun, moon, planets, comets, and asteroids, for both orbital   
 views and finder charts as seen from earth.                                  
                                                                              
                                >> Algorithms <<                              
                                                                              
 The positions of the sun, moon, and planets are computed using the methods   
 outlined in Astronomical Algorithms, by Jean Meeus.  Accuracy should be      
 within a few arcseconds over our lifetimes.  The orbital outlines are        
 computed using less accurate (and faster) "mean elements".  On a scale where 
 overall orbits can be seen, this accuracy is sufficient.                     
                                                                              
 The moon's position is very difficult to obtain with great accuracy.  Whereas
 the planet positions are essentially two-body problems, with perturbations   
 added in, the moon is essentially a three-body problem, being strongly       
 influenced by both earth and sun.  The algorithm given here is claimed to    
 have an accuracy within approximately 10" in ecliptic longitude and 4" in    
 ecliptic latitude.  This is still small relative to the size of the disk of  
 the moon (which is approximately 30'), so graphical representations of       
 eclipses, occultations, etc. should be fairly reliable.                      
                                                                              
 There is no accurate theoretical method to predict the orbit of Pluto into   
 the distant past or future.  Studies have shown its orbit to be chaotic, in  
 the technical sense of the word.  The position for Pluto given here is based 
 on a numerical fit to an integration of the orbit over the period 1885 to    
 2099.  If dates outside this interval are used, no value for Pluto's position
 will be returned.  The accuracy claimed for the heliocentric ecliptic        
 coordinates is 0.6" in longitude, 0.2" in latitude, and 0.00002 AU in radius.
 This accuracy is quite sufficient for locating Pluto.  As a test I plotted a 
 year's worth of positions from the Astronomical Ephemeris (1994) using the   
 plot-from-coordinates feature [Dm, F7, F4, ...] and compared the results with
 the computed positions of Pluto.  On a 2-degree Hubble Guide Star Catalog    
 plot there were no discernable differences, certainly none that would lead to
 mis-identification in the field.  (Version 4.0 had an error that led to small
 but significant differences.  That error is corrected as of Ver 4.01.)       
                                                                              
                                 >> Planets <<                                
                                                                              
 DS3D handles the planets in two groups: those that outshine most if not all  
 of the stars (Mercury, Venus, Mars, Jupiter, and Saturn), and those that     
 require optical aid even to be seen (Uranus [borderline], Neptune, and       
 Pluto).  When scanning the planets [Dm, F6, F1,...] (or automatically if     
 planet display is turned on in [Mm, Modify Configuration, Map Options]) you  
 can choose to add only the bright planets or all planets.                    
                                                                              
 The planets are identifiable by their symbols.  Further identification is    
 obtained by placing the cursor near a planet and using [<SpBar>, <Enter>, F2]
 or using [Dm, F6, F3] to jump from one to the next.  The name and date are   
 displayed in a box at the top left corner of the screen.  For symbols with a 
 circular part, such as the Sun, Moon, Earth, Mercury, Venus, Mars, and       
 Uranus, the location of the planet is the center of the circle.  The         
 asymmetric symbols for Jupiter, Saturn, Neptune, and Pluto, have a small dot 
 added near the center of the symbol for positioning.                         
                                                                              
                                                                              
                                                                              
 ============================= >> SUN AND MOON << ============================
                                                                              
 Among the solar system objects, the sun and moon are drawn to scale, with a  
 certain minimum size.  The shape of the moon indicates its correct phase and 
 orientation in the sky.  If you are on a whole-sky map, the sun and moon will
 be shown disproportionately large.  As you zoom in beyond a certain point,   
 the scale of the map will catch up with them.  Beyond that point the sun and 
 moon will be drawn to the correct scale of the map.                          
                                                                              
                                                                              
 ========================= >> COMETS AND ASTEROIDS << ========================
                                                                              
 [Dm, F6, F2 ...]                                                             
 Comets are interesting observational targets, although beginners often have  
 difficulty locating them because they move from one night to the next and    
 accurate information is sometimes hard to obtain.  For success in comet      
 observation you need an up-to-the-minute information source and the ability  
 to make orbital computations.  DS3D provides the computational side, and our 
 Comet Watch newsletter provides the information source on newly discovered   
 comets.  For the comet options to remain useful you will need to stay current
 on the orbital elements of newly discovered comets and enter them into the   
 comet/asteroid database. (See [Mm, Catalog & Order Form]).                   
                                                                              
                    >> Scanning for Comets and Asteroids <<                   
                                                                              
 [F6, F2, F1, ...]                                                            
 This option lets you scan one or more of your comet/asteroid database files  
 for any comets or asteroids that meet whatever criteria you set.  The        
 information given for each object is:  R.A., Dec., Elongation, predicted     
 magnitude, and rise/set information in graphical form.  Magnitude estimates  
 for comets are notoriously unreliable, but they can give a good idea if a    
 comet will be visible at all.  (Whether magnitude information is given       
 depends on the data available for the given comet.)  As you scroll you are   
 given the opportunity to "select" any number of the objects for display.     
                                                                              
 Scanning the database is a good idea if you ever think you have found a new  
 comet.  You may report a comet that has already been found or has been around
 before and has a known orbit.                                                
                                                                              
                >> Comet/Asteroid Paths for a Range of Dates <<               
                                                                              
 [Dm, F6, F2, F2, ...]                                                        
 Finder charts for comets and asteroids can be plotted on any kind of base    
 map.  It is recommended that you start with the Default Map where you can see
 the overall motion through the sky, then zoom to a smaller scale map for     
 finer detail with more stars added to aid in finding the object with a       
 telescope.                                                                   
                                                                              
 A word here about comet tails is in order.  The tail displayed by the program
 is in no way a prediction of actual tail length: it is fixed at an artificial
 1/10 AU length (about 10 million miles).  However, it does reflect the effect
 of distance and phase on apparent tail length, and it is shown at the correct
 position angle on the sky for an ion tail, which points directly away from   
 the sun.  Some comets have anti-tails and dust tails are sometimes quite     
 curved.  The length of the displayed tail is the length the tail would appear
 if it were actually 1/10 AU long.  If the observed tail is half that long you
 know that the physical length is about 5 million miles.  The plotted tail is 
 thus not a prediction, but it turns out to be a good measuring stick.        
                                                                              
 Another question will arise when plotting comets, asteroids, planets, etc. on
 "time referenced maps" such as the Default Map, a Circular Day-and-Time map, 
 or a Horizon-View map.  By definition these maps are set for a particular day
 and time, yet a path for a range of dates is, by definition, extended over a 
 range of dates!  How can the two be meaningfully combined?                   
                                                                              
 On "time referenced maps" two paths are optionally shown: one follows the    
 path of the object relative to the stars, the other follows the path of the  
 object relative to the horizons.  By typing S, H, or B you can select the    
 path relative to the Stars, the Horizon, or Both.  If you choose B, The      
 starting day for the object will match the date of the map, so the two       
 initial marks will coincide.  But then, since the sky rotates over the       
 plotted interval, the two paths diverge.  The normal plot (+ marks with a    
 tail for comets) indicates the path relative to the stars.  The path relative
 to the horizon is marked with X's.  This is the path that shows how the      
 object's position will change relative to the horizon observing at the same  
 time each night.  This plot is very useful for seeing how long the object    
 will remain in the observable portion of the sky or whether it will be a     
 "horizon hugger".                                                            
                                                                              
                       >> Comet & Asteroid Ephemerides <<                     
                                                                              
 An ephemeris (e-phem'-er-is, plural: e-phe-mer'-i-des) is a numerical listing
 that shows where a celestial body will be in the sky over a range of dates.  
 The headings are as follows:                                                 
                                                                              
  (The range of dates goes down the left side of the page.)                   
                                                                              
   R.A. & Dec --Position in the sky in equatorial coordinates                 
   R          --Distance from sun to object                                   
   Delta      --Distance from earth to object                                 
   Elong.     --Elongation: angle from sun to object as seen from earth       
   Phase      --For a comet this tells to what extent the tail points away    
                from us.  90 degrees is directly across our line of sight.    
   PA         --Position angle: the angle of the tail in the sky measured     
                counterclockwise from north                                   
   Mag.       --Estimated magnitude (emphasis on estimate for comet           
                magnitudes!)  Magnitude data is optional and will not be      
                displayed if the required data is missing.                    
                                                                              
 Output from an ephemeris can be sent to the printer or a text file in ASCII  
 format.                                                                      
                                                                              
                          >> Comet Orbital Elements <<                        
                                                                              
 Orbital elements are six numbers that describe a comet orbit's size, shape,  
 orientation in space, and time of closest approach to the sun.               
                                                                              
 The elements have strange sounding names, but you don't have to know anything
 about them to be able to plug them into DS3D.  If you subscribe to Comet     
 Watch you will be among the first to know when a new comet is discovered or  
 when a returning comet has been "recovered".  Comet Watch gives you the six  
 numbers the program needs to know.  Simply plug them in and let the program  
 go to work.                                                                  
                                                                              
 The six magic numbers for comets are as follows:                             
                                                                              
                                                                              
 T     : Time of perihelion passage--when the comet is closest to the sun     
 e     : Eccentricity--a measure of the elongation of the orbit.  For a       
         circle, e=0.  For a parabola, e=1.  Above 1 the orbit is a hyperbola.
 q     : Perihelion distance--closest approach to the sun                     
 PERI  : Argument of perihelion--measures the orientation of a comet's orbit  
         within its own orbital plane.  (Symbol = lower case Greek Omega.)    
 NODE  : Longitude of the Ascending Node--locates where the comet's orbit     
         crosses the ecliptic plane.  (Symbol = upper case Greek Omega.)      
 i     : Inclination--the angle between the orbital planes of the earth and   
         comet.                                                               
                                                                              
 The equinox of the elements needs to be specified. Until recently comet     
 elements were provided relative to the equinox of 1950.0, called the B1950.0 
 system.  Now all comet elements are specified relative to the equinox of     
 2000.0, called the J2000.0 system.  Unless you are dealing with old data,    
 leave the setting on J.                                                      
                                                                              
 In addition, you have the opportunity to enter magnitude information.  If you
 have the absolute magnitude for the comet you can enter it directly.  If you 
 know the magnitude on a given date you can enter that and the program will   
 work backward and compute the absolute magnitude for you.  You will have to  
 enter a constant (k) that describes how the brightness varies with distance  
 from the sun.  This is not generally known for newly discovered comets, so a 
 value of 10 is used until a better value is determined.                      
                                                                              
                                                                              
                        >> Asteroid Orbital Elements <<                       
                                                                              
 Asteroid elements are the same as Comet elements except for a few minor      
 differences.  Instead of the perihelion distance (q), the semimajor axis (a) 
 is given.  Instead of the time of perihelion passage, an "epoch" date is     
 specified, and the value of the Mean Anomaly (M), which is related to the    
 comet's position in its orbit, is given for that date.  Magnitude is         
 specified by a pair of parameters that model the variation of brightness with
 distance from the earth and distance from the sun.                           
                                                                              
                              >> Comet Recovery <<                            
                                                                              
 [Dm, F6, F2, F5]                                                             
 Most comets can be tracked only when they are at the inner part of their     
 orbits.  Because they are made of volatile material that outgasses, they are 
 subjected to jet effects, commonly referred to as "non-gravitational" forces.
 As a result, when a comet returns it may be advanced or delayed in its orbit 
 by an unpredictable amount.  The predicted position of a returning comet may 
 not be accurate enough to allow it to be spotted without a hunt.  DS3D can   
 trace out a search path in the sky for comet recovery purposes, based on the 
 assumption the return time is the only orbital parameter significantly       
 affected.                                                                    
                                                                              
                      >> Understanding Orbital Elements <<                    
                                                                              
 If you want to visualize orbital elements, think of a book resting on a      
 table.  The surface of the table represents the plane of the earth's orbit.  
 The cover of the book represents the plane of the orbit of the comet or      
 asteroid.  You can cut out a paper ellipse and tape it on the cover of the   
 book.  The shape of the ellipse is determined by the eccentricity (e) and its
 size is determined by any linear dimension, in this case of comets the       
 distance from the focus to one end of the ellipse (q) is used.  In the case  
 of asteroids the "long radius" called the semimajor axis is used.  (Since    
 comets may have open ended orbits they may not have a measurable semi-major  
 axis.)                                                                       
                                                                              
 The angle of perihelion (PERI) is the angle of rotation of the ellipse       
 relative to the binding of the book.  The inclination (i) is the angle the   
 cover is lifted as the book is opened.  The longitude of the ascending node  
 (NODE) is the angle of the book binding relative to the edge of the table as 
 the book is rotated on the surface of the table.  These five elements        
 determine the geometry of the orbit.  For comets, the time of perihelion     
 passage (T) pins down its location for one specific time.  For asteroids the 
 time called the Epoch is chosen arbitrarily and a parameter related to its   
 starting position (M) is given.  The Epoch doubles as an indicator of how far
 out of date the elements are.  Asteroids come around frequently, so the      
 elements must be updated periodically.  Comet elements also need updating,   
 but they typically return at long intervals, and various forces make their   
 return dates rather uncertain.                                               
                                                                              
 Once the starting conditions are known, Newton's law of Gravity takes over   
 (masquerading in the form of Kepler's laws) and determine the rate of motion 
 and allow prediction of where the comet will be in its orbit at any other    
 time.                                                                        
                                                                              
 The bottom line is, you must type the right numbers into the right boxes to  
 let the computer do its thing correctly.                                     
                                                                              
                                                                              
                       >> Comet/Asteroid Element Files <<                     
                                                                              
 If your interest in comets is purely observational, you can delete most long 
 period comets after they have faded.  They will never return in your         
 lifetime.  However, for other aspects of comet study you may want to collect 
 orbital data to compare comets even after they are long gone.  For instance, 
 some recent comets are suspected to be returns of ancient comets.  Comparing 
 orbital elements (or 3-D views of the orbits) can give an indication if this 
 is the case.  Asteroids, on the other hand, stick around, but their elements 
 need updating frequently.                                                    
                                                                              
 An optional data disk has data on over 1100 comets (Based on Brian Marsden's 
 Catalog of Cometary Orbits) dating back to the first confirmed sighting of   
 Comet Halley in 240 BC (which astronomers refer to as the year -239.  For    
 astronomers, the year preceding 1 AD is 0 AD.  For historians the year       
 preceding 1 AD is 1 BC.)                                                     
                                                                              
 If you collect large amounts of orbital data, you can best organize the data 
 by keeping it in multiple files.  The CURRENT.ACF and RECENT.ACF and         
 ASTEROID.ACF files are on the disk initially.  Other *.ACF files may be added
 without limit.                                                               
                                                                              
 Comet data can be copied to a new file or between existing files.  To do     
 this, select a comet in an existing file, and choose the Copy option shown at
 the bottom of the page when its elements are displayed.  A menu of existing  
 comet files will be shown allowing you to select which file to copy it to.   
 If you want to start a new file, type <Insert> to enter the new file name.   
                                                                              
 Another option at the same point where the copy option is offered, is to     
 delete an object.  You may well want to enter new comets in CURRENT.ACF, then
 copy it to RECENT.ACF and delete it from CURRENT.ACF when it is no longer    
 easily visible.                                                              
                                                                              
 The program CONVERT.EXE is a separate program supplied with DS3D which must  
 be in the same subdirectory as the orbital element files.  It will convert   
 old style *.CFL files from versions 2.x and 3.x to the newer *.ACF files.    
 The format was changed to allow for mixing comet and asteroid elements in one
 system.  CONVERT.EXE will also convert files to or from *.TXT files in ASCII 
 format that can be read, edited, or organized with a text editor or word     
 processor. If text files are to be converted back to *.ACF form, they must be
 in pure ASCII and follow the exact pattern of the text files produced by     
 CONVERT.EXE.  (The number of spaces between the numbers is unimportant.)     
                                                                              
                                                                              
 ================================ >> ORBITS << ===============================
                                                                              
 [Dm, F6, F1, F4, ...]  or  [Dm, F6, F2, (F3/F4), ...]                        
 The orbits of planets, comets, and asteroids can be viewed from space.  In   
 the process of specifying what is to be shown you can set the viewer's       
 location in space.  The direction of view will always be toward the sun.  The
 stars shown in the background are the correct stars for the chosen point of  
 view.                                                                        
                                                                              
 You can modify the viewer's location either with [Dm, F6, F4] or by using the
 cursor to indicate a new view direction.  If the cursor is used, the new view
 direction will be such that the viewer and sun line up with the point in the 
 sky chosen by the cursor.  You can "walk" your way around the sky with this  
 method.                                                                      
                                                                              
 Once orbits are drawn, if any further planet, comet, or asteroid positions   
 are displayed they will be positioned on their orbits.  This is one way you  
 can visualize how the earth and a comet, for instance, are moving in relation
 to each other.  [Dm, F6, F4] (Object ID.) will work for solar system objects 
 on their orbits as well as on finder charts.                                 
                                                                              
                                                                              
 =========================== >> DEEP SKY OBJECTS << ==========================
                                                                              
 [Dm, F7, F1, ...]                                                            
 Deep Sky Objects include galaxies, nebulae, star clusters, and various other 
 categories of non-stellar objects.  As DS3D plots deep sky objects they are  
 added to a list in memory.  As you move from one map to another you can      
 either start a new list or append objects to the existing list for a maximum 
 or 1000 objects.  Those objects that you label are flagged and become part of
 an observing list which you can print out separately.  You may want to create
 several maps for a given night and accumulate the labeled objects into a     
 single observing list, or you may wish to print shorter observing lists to go
 with each printed map.  (As we have used DS3D we have come to prefer the     
 second method.  We print each map and staple it to its observing list.  This 
 becomes a handy packet, combining features of an atlas, catalog, and         
 commentary.)                                                                 
                                                                              
 First decide whether to create a new list or append to the current list.     
 Then select the limiting magnitude for non-stellar objects.  This selection  
 is independent of the limiting magnitude for stars.  (Only dark nebulae      
 bypass the magnitude screening.  If you include dark nebulae, all of them in 
 the database will be shown.)  The limiting magnitude you select should depend
 on the size of your telescope, the darkness of your observing site, and your 
 observing experience.  The Messier list goes down to about 11th magnitude.  A
 12 inch telescope with dark skies will take you a little past 13 for         
 galaxies.  Magnitude is not the only thing that affects an object's          
 visibility.  Some objects are bright, but hard to see because they are large 
 and their surface brightness is low.                                         
                                                                              
 If you are a registered user, you may select objects from the entire database
 or from more specialized categories.  If you have an unregistered program you
 will be limited to the Messier list, or user-defined categories limited to   
 subsets of the Messier list.  The Messier list is a good starter list        
 containing many of the brighter objects.  The "Herschel 400" list is the     
 basis of an observing program sponsored by the Astronomical League.  It picks
 up the bright objects Messier missed and includes some of the more           
 challenging objects in the NGC (New General Catalog).  If you are working on 
 a Messier Marathon or working toward a "Herschel Club" certificate, DS3D is  
 made to order for your needs.                                                
                                                                              
 You may define up to four categories of your own.  The categories you define 
 can be totally arbitrary: "My Favorite Galaxies", "Objects I Can See From My 
 Back Yard", "Planetary Nebulae That Don't Simply Look Like Stars", etc.  (See
 [Mm, Extended Help, User Defined Categories] for instructions on setting up  
 and assigning objects to your own categories.)  If you have set up one or    
 more user defined categories you may choose one of them at this point.       
                                                                              
 Finally you can select within a category the types of objects you want to    
 observe.  Use the <Enter> key or <Arrow> keys to move the selection bar, and 
 type <Space> to select an object type.  You may choose one, all, or any      
 combination of object types.                                                 
                                                                              
                                                                              
                             >> Deep Sky Symbols <<                           
                                                                              
 When deep sky objects are too small to be clearly drawn to the scale of the  
 map, the object is represented with a standard sized symbol.  When a map is  
 zoomed sufficiently, the objects will be scaled proportionately.             
                                                                              
 Galaxies whose size, shape, and position angles are included in the database 
 are shown as ellipses of appropriate dimensions and orientation.  The Large  
 and Small Magellanic Clouds are scaled this way even on a whole sky map.     
 With any zooming at all, M 31 and M 33, the Andromeda and Triangulum galaxies
 are shown to scale.  But even small galaxies such as those in the Virgo      
 cluster are shown to scale when zoomed in sufficiently.                      
                                                                              
 Star clusters, planetary nebulae are scaled similarly, but with circular     
 symmetry.                                                                    
                                                                              
 Nebulae are exceptions.  The database does not include outline information   
 for nebulae, show they are indicated by a small box.  As zooming takes place 
 the box begins to grow, but the sizes would be very distracting and not very 
 informative, because some nebulae are huge, and don't look like boxes!       
 Therefore, there is a maximum size.  Nebulae (both dark and bright) are shown
 as either minimum size symbols, proportionately scaled if you hit it just    
 right, or a maximum size symbol.                                             
                                                                              
 The symbol for a Cluster with Nebulosity is a dotted circle with a box in it.
 The cluster symbol will grow proportionately, and so will the box.  I would  
 be tempted to simply group the "cluster with nebulosity" items with the      
 clusters, but that would categorize the Orion Nebula and the Lagoon Nebula as
 clusters.  If, on the other hand I grouped them with nebulae, the Pleiades   
 would be categorized as a nebula!  This is definitely a mixed group.         
                                                                              
                                                                              
                        >> Labeling Deep Sky Objects <<                       
                                                                              
 Once deep sky objects are displayed, they may be screened individually and   
 labeled with the primary or secondary name, deleted, or left on the screen   
 unlabeled.  Objects that are labeled are thereby selected for the current    
 observing list.  Objects may be selected one at a time with the cursor.  As  
 an object is identified a small box is displayed that indicates the          
 approximate size the label will be on the printout.  It may be positioned    
 with the arrow keys.  A line connecting the object with its label allows you 
 to clearly identify objects even in cluttered areas of the sky.  Some objects
 are obvious without their symbols (such as the Pleiades, Hyades, the Coma    
 Berenices Cluster, etc.)  For cases like these you may turn the symbol off/on
 with the <F4> key, leaving the name to stand on its own.  In other cases you 
 may wish to remove a label, using the <F3> key, but leave the symbol on the  
 chart.  The object can be labeled with the first or second name listed by    
 typing <F1> or <F2>.                                                         
                                                                              
 Along with the label, three windows will pop up.  One is a menu for the      
 function keys, one is a summary description of the object, and the third,    
 which is initially blank, is space for your observing notes.  You can scroll 
 the description window with the <PgUp>, <PgDn>, <Home>, and <End> keys.      
                                                                              
 If you want to add an object to a user-defined category, type <F5>.  Position
 the cursor on one of the category labels, and type the space bar.  Typing the
 <Space> bar again will remove the object from the category.                  
                                                                              
                                                                              
 =============================== >> ALMANAC << ===============================
                                                                              
 In its present incarnation the [Mm, Almanac] feature has three pages of      
 information.  Page 1 gives the Solstices and Equinoxes for the currently     
 active year along with the dates and times of the moon phases throughout the 
 year.                                                                        
                                                                              
 Page 2 gives a table of planet position data for the current day and time.   
 When planets and the sun and moon are displayed graphically their positions  
 are based on these same calculations, but the tabular form is included here  
 in case you need access to the numbers directly.  The following summarizes   
 the table on Page 2.                                                         
                                                                              
 COLUMN HEADINGS:                                                             
   R.A.       --Right Ascension: angle in hours, not degrees, measured        
                eastward along the equator from the Vernal Equinox.           
   Dec        --Declination: angle above or below the celestial equator       
                measured in degrees.                                          
   Long       --Ecliptic Longitude                                            
   Lat        --Ecliptic Latitude                                             
   Az         --Azimuth: angle in degrees measured eastward along the horizon 
                from due south.                                               
   Alt        --Altitude: angle in degrees above or below the horizon         
   Elong      --Elongation: the angle of the planet from the sun measured     
                along the ecliptic.                                           
   Phase      --Angle between your line of sight and the direction of sunlight
                falling on an object.  Full phase is 0 degrees.               
   Dist       --Distance from the earth in AU's, for planets, in earth radii  
                for the moon.                                                 
   Diam       --Angular diameter measured in minutes of arc.                  
                                                                              
 Rise-Set Information:                                                        
 Times of rise and set are shown graphically for ease of use.  The hours of   
 darkness and twilight are indicated at the top of the page.  Times are       
 centered on local midnight, regardless of what time zone you are using.  (eg.
 if you use daylight saving time you will notice that 1 am, not 12 am is at   
 the center.)                                                                 
                                                                              
 The dashed lines indicate the times the moon and planets are above the       
 horizon.  The double lines indicate when they are more than 20 degrees above 
 the horizon, a hypothetical "smog line".  Even if there is no smog, at 20    
 degrees above the horizon you are looking through 3 times as much atmosphere 
 as when you look directly overhead.                                          
                                                                              
                                                                              
 ========================== >> THE OBSERVING LIST << =========================
                                                                              
 The [Mm, Observing List] option allows you to browse the current observing   
 list on the screen, add notes to the User Log, delete objects from the list, 
 print the list, save it as a named file to be called back later, send it to  
 an ASCII file allowing it to be accessed by a word processor.                
                                                                              
 The [Mm, Observing List] Browse Function prints out the catalog description  
 of the object, an optional rise/set graph, and optionally, any observing     
 notes from the log file.  If rise/set graphs are included, the hours of      
 darkness and twilight will be presented at the top of each page.             
                                                                              
 Because of the amount of material to be printed about each object you may    
 want to edit the observing list before printing it out.  You can print a     
 simplified one line description, omit the observing notes, omit the rise/set 
 graph, to an ASCII file and edit it with a word processor.                   
                                                                              
 If you load an observing list before displaying a star map, the current list 
 will display as soon as the map is displayed, ready for labeling to be done. 
                                                                              
                                                                              
 ========================== >> THE OBSERVING LOG << ==========================
                                                                              
 Notes may be added to the observing log during the naming cycle when an      
 object is selected on a map, or from the [Mm, Observing List] option.  If you
 are returning from an observing session the easiest way to enter your notes  
 is to enter [Mm, Observing List], load the desired list (assuming it was     
 saved earlier), then enter Browse.  From Browse type E to enter edit mode.   
 Editing from the graphics screen is also possible, but the display will      
 flicker as characters are typed and there is less space to display what has  
 already been written.  The display edit is good for brief comments while an  
 object is being displayed, or for editing on a laptop in the field as soon as
 an object has been observed.  Both text and graphics windows will scroll.    
 The maximum size of a comment record for a single object is about the        
 equivalent of a full page of single spaced typed comments.                   
                                                                              
 You can leave the log window by typing <F10> or <Esc>.  Either option will   
 allow you to save your comments or discard them.                             
                                                                              
                                                                              
 ======================= >> USER DEFINED CATEGORIES << =======================
                                                                              
 User defined categories of deep sky objects are created or deleted in the    
 [Mm, Observing List] option.  Once a category is created, items can be added 
 to the list one at a time from a star map, or while browsing the observing   
 list, or by dumping an entire observing list into the category.              
                                                                              
 For example, here is how you could create a category of "Barred Spiral       
 Galaxies":                                                                   
                                                                              
 Plot a map, add galaxies down to whatever magnitude limit is desired, cycle  
 through the naming/selection process, deleting all galaxies except the SB    
 type.  By simply labeling the barred spirals you add them to the current     
 observing list.  Now go back to [Mm, Observing List], create a "Barred       
 Spiral" category, and dump the observing list into the category.  As you run 
 across other barred spirals they can be added to the list one-by-one or a    
 batch at a time.  Objects being added to a category are screened by the      
 program, so there is no danger of duplication.                               
                                                                              
 Once a user-defined category has been established, it may be browsed from    
 [Mm, Object Categories, Browse Category].                                    
                                                                              
 (The [Mm, Extended Help, Overview for Active Observers] note contains another
 application of a user-defined category.)                                     
                                                                              
                                                                              
 ============================== >> STEREO 3-D << =============================
                                                                              
 On Screen: [Dm, F9, ...]    Printouts: [Dm, F10, (F2 or F3), ...]            
 Space is 3-dimensional.  The sky we see is a two dimensional surface because 
 of the limitations of our depth perception.  At great distances all things   
 look the same distance away, hence we seem to be at the center of a sphere.  
 In other words, the dome of the sky is an illusion.  It takes the illusion of
 stereo graphics to dispel the illusion of the sky.                           
                                                                              
 To see 3-D you need two points of view that are sufficiently far apart       
 compared to the distances of the objects being viewed.  In a room, normal eye
 spacing gives ample depth perception.  Depth is easily judged 10 or 20 feet  
 away by eyes that are about 2.5 inches apart: a factor of 50-100 eye         
 spacings.  Keep this in mind when it comes to plotting stereo views of the   
 stars.  Use the [Dm, F9, F3] option to set the 3-D parameters.  A simulated  
 "eye spacing" of a few tenths of a light year will bring out depth well into 
 the distance among the stars.  Overdoing the eye separation is like trying to
 look at something an inch or two in front of your face.  On the other hand,  
 increased eye spacing can bring out the relative depth at greater distances. 
 Be flexible and experiment.  See for yourself the difference changing the eye
 spacing makes for different views.                                           
                                                                              
 To see 3-D you may need a viewer.  Most people, however, can, with patience, 
 teach themselves to view the 3-D views without a viewer, one eye looking at  
 each frame.  (Most people do this by relaxing their eyes to look parallel, so
 the left eye looks at the left frame while the right eye looks at the right  
 frame.  Others cross their eyes, so each eye looks at the opposite frame.    
 Either method of display can be selected.)  Using a viewer makes the process 
 easier.  The stereo views are printed at the spacing of the viewer lenses,   
 which in turn are approximately the spacing of your eyes.  The viewer makes  
 the images appear to be at infinity, so looking along parallel lines of sight
 comes more naturally.  The brain fuses the information from the two slightly 
 different flat pictures into a single 3-dimensional image.                   
                                                                              
 To see 3-D using parallel focus without a viewer, the boxes should be the    
 same spacing as your eyes.  On the other hand focusing inward slightly can be
 easier to achieve, so when you are starting out you may want to make smaller 
 boxes.  If you use a viewer, the boxes should be exactly the spacing of the  
 lenses regardless of the actual spacing of your eyes.  The lenses will       
 compensate for your eye spacing.                                             
                                                                              
                        >> Planet Depth / Star Depth <<                       
                                                                              
 If planets, comets, or other solar system related objects are in the field   
 they will be so close relative to the stars that the stars will be flat in   
 the background.  If your eyes are space properly to see depth in the stars,  
 however, they will be much farther apart than the size of the solar system,  
 so the solar system itself will not be visible.  To expedite the process of  
 showing one or the other level of depth, you can choose "Planet Depth" or    
 "Star Depth" 3-D.  If you choose Planet Depth, the stars will be shown flat. 
 If you choose Star Depth, the planets will be temporarily eliminated from the
 view.  They will return when you zoom back out.                              
                                                                              
 Once either 3-D option has been chosen, for either screen display or         
 printout, you will be presented with a square zoom box to position and scale 
 as you see fit.  When you have the view you want, type <Enter> and the stereo
 pair will be displayed on screen.  If you selected the printing option you   
 can print at this point or back out of the printing with <Esc>.              
                                                                              
 Some of the things to notice when viewing the stars in 3-D:                  
 --Some stars are bright because they are close, whereas others are bright    
   because they are BRIGHT.                                                   
 --Some pairs of stars are close together in the sky but far apart in space.  
   Other stars are far apart in the sky but close to each other (and us) in   
   space.                                                                     
 --Some familiar constellations contain actual star groupings, others only    
   apparent groupings.                                                        
                                                                              
 When comet orbits are seen in 3-D the main point of interest is the          
 orientation of the orbits relative to the earth's orbital plane.  Most of the
 solar system is flat, but comets come in from all angles.  The inclinations  
 stand out dramatically in this format.  If you back far enough away you can  
 see the dramatic inclination of Pluto's orbit compared with the rest of the  
 planets.                                                                     
                                                                              
                                                                              
 ============================ >> THE DATABASES << ============================
                                                                              
 DS3D uses a star database provided by the National Space Science Data Center 
 called "Skymap," based largely on the SAO (Smithsonian Astrophysical         
 Observatory) star catalog.  The depth of the full database (close to 250,000 
 stars) is adequate for most star-hopping needs of telescope users tracking   
 faint fuzzy objects between the stars.                                       
                                                                              
 One attractive feature of the Skymap database is its numerous data fields per
 star.  Only a small number of the fields were kept for access by DS3D.  One  
 charactistic of the database that most appealed to me was that a parallax (or
 distance) measurement was given for most stars.  Most other large star       
 databases lack this information.  Granted, distance is not accurately known  
 for most stars, and the reliability of the data varies greatly within the    
 database, but the broad coverage of distance data in Skymap is what puts the 
 3-D in DS3D!  As long as the user is aware that distance is a difficult      
 measurement and the distance data here, or anywhere, for that matter, is not 
 definitive, the 3-D star maps give a reasonable sense of the distribution of 
 stars in the solar neighborhood.                                             
                                                                              
 The non-stellar database used in DS3D is the SAC (Saguaro Astronomy Club)    
 database.  Members of the Phoenix-based astronomy club, together with an     
 Arizona astronomer with expertise in the history of the errors in the NGC    
 catalog compiled a computerized version of the NGC (New General Catalog) with
 corrections and annotations, purged of its "non-existent" objects, and       
 supplemented by numerous entries from other catalogs.  The final count comes 
 out to just under 10,000 objects.  It is a database well suited to the needs 
 of amateur astronomers.                                                      
                                                                              
 The third database is Version 1.1 of the GSC (Hubble Guide Star Catalog), a  
 database of approximately 18 million entries, mostly stars.  The data is     
 available on two CD Roms from the Astronomical Society of the Pacific, 390   
 Ashton Ave., San Francisco, CA 94112.  The depth of the database exceeds the 
 light grasp of most amateur telescopes to the point that you can produce     
 field-of-view charts that show essentially every star visible in the         
 eyepiece.  The presentation of open star clusters is spectacular.  Globular  
 star clusters are also scanned in great detail, but the inner areas are      
 frequently left blank when the limits of the scanning technology were        
 reached.  The data has uneven magnitude cut-offs in different areas of the   
 sky, but in general the limiting magnitude is between 14th and 16th          
 magnitude.  Some of the data entries are actually artifacts, such as optical 
 spikes around bright stars, but the majority of these have been identified   
 and are assigned a separate classification.                                  
                                                                              
 Unlike Skymap, the GSC has very little information per star: position,       
 brightness, tentative classification as a star, non-star, etc., and          
 information unlikely to interest amateurs such as the uncertainties in the   
 measurements and information about the source plates.  There is no data on   
 distance or spectral class, so the data is monochrome and flat.  Color for   
 GSC maps is used to encode the classification, white being stars, and various
 colors representing various categories of non-stars.  Still, the sheer volume
 of data in a form accessible to PC's is an incredible resource for amateurs. 
                                                                              
                                                                              
 ============================ >> ABBREVIATIONS << ============================
                                                                              
 The NGC (New General Catalog of non-stellar objects), Burnham's Celestial    
 Handbook, and other sources have used a series of abbreviations for verbal   
 comments on objects.  These abbreviations have been carried over into the SAC
 database and appear in the notes section of the basic information window.    
 They take a little practice to read fluently.  Here they are:                
                                                                              
 !    remarkable object                  diam diameter                        
 !!   very remarkable object             dif  diffuse                         
 am   among                              E    elongated                       
 att  attached                           e    extremely                       
 bet  between                            er   easily resolved                 
 neb  nebula, nebulosity                 F    faint                           
 B    bright                             f    following                       
 b    brighter                           g    gradually                       
 C    compressed                         iF   irregular figure                
 c    considerably                       inv  involved                        
 Cl   cluster                            irr  irregular                       
 D    double                             L    large                           
 def  defined                            l    little                          
 deg  degrees                            mag  magnitude                       
                         (Continued)                                          
                                                                              
 M    middle                             S    small                           
 m    much                               s    suddenly                        
 n    north                              s    south                           
 N    nucleus                            sc   scattered                       
 neb  nebula, nebulosity                 susp suspected                       
 P w  paired with                        st   star or stellar                 
 p    pretty (before F,B,L or S)         v    very                            
 p    preceding                          var  variable                        
 P    poor                               nf   north following                 
 R    round                              np   north preceding                 
 Ri   rich                               sf   south following                 
 r    not well resolved, mottled         sp   south preceding                 
 rr   partially resolved                 11m  11th magnitude                  
 rrr  well resolved                      8... 8th magnitude and fainter       
                                         9...13  9th to 13th magnitude        
                                                                              
 (Other Abbreviations:                                                        
 P w N ( paired with NGC###)                                                  
 P w U ( paired with UGC ###)                                                 
                                                                              
                                                                              
 ======================== >> DEEP SKY OBJECT CLASS << ========================
                                                                              
 Each type of deep sky object has its own classification system.  Here are the
 classes used in the descriptions of open clusters, globular clusters,        
 planetary nebulae, and galaxies (adapted from SAC database documentation.)   
                                                                              
 Open Clusters:  Trumpler type                                                
                                                                              
   Concentration                                                              
     I.  Detached, strong concentration toward the center                     
    II.  Detached, weak concentration toward the center                       
   III.  Detached, no concentration toward the center                         
    IV.  Not well detached from surrounding star field                        
                                                                              
   Range in brightness                                                        
     1.  Small range   2.  Moderate range   3.  Large range                   
                                                                              
   Richness                                                                   
     p  Poor             (<50 stars)                                          
     m  Moderately rich  (>50 stars, <100 stars)                              
     r  Rich             (>100 stars)                                         
                                                                              
   An "n" following the Trumpler type denotes nebulosity in cluster           
                                                                              
 Globular Clusters:  Shapley-Sawyer concentration rating                      
                                                                              
   Globular clusters are rated on a scale of 1 to 12:                         
     1 = very concentrated,  12 = not concentrated                            
                                                                              
                                                                              
 Planetary Nebulae:  Vorontsov-Velyaminov type                                
                                                                              
   1.  Stellar                                                                
   2.  Smooth disk (a, brighter center; b, uniform brightness;                
                    c, traces of ring structure)                              
   3.  Irregular disk (a, very irregular brightness distribution;             
                    b, traces of ring structure)                              
   4.  Ring structure                                                         
   5.  Irregular form similar to diffuse nebula                               
   6.  Anomalous form, no regular structure                                   
                                                                              
   (Some complex forms may combine two types.)                                
                                                                              
 Galaxies:  Hubble classification                                             
                                                                              
   E  Elliptical Galaxy:                                                      
        E0 is spherical -- E7 is highly flattened                             
        Subgroups; 'd' (dwarf), 'c' (supergiant), 'D' (diffuse halo)          
                                                                              
   S  Spiral Galaxy:                                                          
        Sa: tightly wound arms                                                
        Sb: moderately wound arms                                             
        Sc: loosely wound arms                                                
                                                                              
   SB Barred Spiral Galaxy:                                                   
        SBa: tightly wound arms                                               
        SBb: moderately wound arms                                            
        SBc: loosely wound arms