Generic HP-48 Calculator Compass
                             by Junichi Steven Sato

-Introduction-

Whether you're lost in the Sahara Desert in Africa, the Great Sandy Desert in
Australia, or in an unknown city in the United States, you can use the HP-48
Calculator Compass program to determine which way you're heading.  To receive
accurate readings, though, you must:

     1)  have a HP-48 with a Calculator Compass program
     2)  have the correct time on the calculator
     3)  know whether you're in the Northern or Southern Hemisphere, and
     4)  have the sun shining.

Start the program by evaluating 'COMPASS'.  This program will not work properly
if system flags -17, -18 and/or -55 are/is set.  The program creates the
reserved variable 'PPAR' if one does not exist already, and may modify it if
there is one.  'COMPASS' does not require anything from the stack.

When the program prompts for the hemisphere, enter "S" if you're in the
Southern Hemisphere and enter anything else if you're in the Northern
Hemisphere.  The screen will then display an arrow pointing to a certain
direction.  Position the calculator so that this arrow is pointing toward the
sun.  This can be done in many ways.  One way is to take a pen or a similar
object and stand it perpendicular to the earth.  Position the calculator so
that the object is casting a shadow over the arrow, which in turn, should be
pointing directly at the object.  Do not look directly into the sun!  Press the
ATTN key.

The screen should then be displaying two arrows.  The shorter one should be
pointing at the sun.  The longer one points north.  Press ATTN again to return
to the stack.

-How the program works-

As one may suspect, the program does not use magnets to find which way north
is.  Rather, it uses the time of day and the position of the sun.  The program
internally builds itself an analog clock.  In the Northern Hemisphere, if the
hour hand of an analog clock is pointing toward the sun, south is halfway
between the "12" and the hour hand.  North, needless to say, is the other way.
In the Southern Hemisphere, if the "12" is pointing toward the sun, north is
halfway between the "12" and the hour hand (Source: Hachiro Asano's "Mind
Test," pp. 168-9).  Take a closer look at how the program works by using the
DEBUG command.

-Notice-

The program 'COMPASS' is freeware.  It is not to be bought or sold.  The
program and documentation may be copied freely and doing so is encouraged
provided that the material are not altered in any way.  Nobody but the user may
be held responsible for any consequential damages resulting from the use and/or
misuse of the program and/or documentation.

The user is encouraged to use or improve the program for the development of
other programs.  Please be sure, when doing so (although not required), to send
your ideas and/or modifications to:

                               Junichi Steven Sato
                               c/o Compass Program
                         707 West Waveland Avenue, #311
                             Chicago, IL  60613-4112
                       (Address may change without notice)

                           or E-Mail at jssato@aol.com

-HP-48 Calculator Compass Releases-

Release      Date         Checksum     Bytes

Version 1.0  August 1991  #44571d      488
Version 1.1  August 1991  #47093d      485.5
Version 1.2  June 1992    #28929d      531.5

-Warning-

Sunlight is known to dissolve lead display.  Do not keep your calculator
exposed to direct sunlight for a prolonged period of time.

-Conclusion-

The next time you're lost in the Sahara Desert, this program will give you an
answer to the question "Which way is north?"

...Which in turn leads you to a second question: "What am I doing in the Sahara
Desert with a HP-48??"

                                        Junichi S. Sato
                                        June 21, 1992