This astronomy stack is designed to ease the calculations associated with rising, setting and positions of the sun and planets. The positions are calculated using low-precision Chebyshev polynomials found in the annual publication "Almanac for Computers" published by the U.S. Naval Observatory. The items are entered in hidden background fields on each card, one field for R.A. and one for declination. These may be made visible and must be updated each calendar year. For some planets the position calculations may take 15 seconds or so and is designated by a sad face. The altitude/azimuth calculations are quicker and are denoted by a smiling face.
The observers latitude, longitude, altitude and hours difference from UT are entered on the first card. The DST button is automatically set if Daylight Savings Time is in effect. Universal Time and Sidereal Time are calculated as well as the Julian Date. A Jovian Galilean satellite button is seen on the Jupiter card and this links to my JSAT emulation program (available on GEnie or from me).
The time for Algol's next minimum is calculated and displayed on card 1.
Holding down the shiftKey bypasses RA and Dec. calculations.
Holding down the optionKey forces the calculations to be performed.
Planetary elongations are calculated and displayed on the first card.
The button "Update for Today" updates all cards and fields to the present time/date and takes about 1.5 minutes to run. It is very useful at the beginning of a session.
Jupiter Galilean Satellite Timing Predictions are displayed for the current date. The file for calendar year 1989 is included (1989). Set the correct pathname in the card script on card Jupiter. Additional information may be obtained from John Westfall, ALPO, Box 16131, San Francisco, CA, 94116, USA
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