-- card: 8682 from stack: in
-- bmap block id: 0
-- flags: 0000
-- background id: 3340
-- name: One


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About Almanac -- 1

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   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 directly 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.
   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.
    A card is given to assist with astrophotography.  The formuale are based on Barry Gordon's book, "The fx System of Astrophotography".
   A planetary conjunction card is now included.  Enter the threshhold value in degrees and all planetary conjunctions less than the theshhold value will be listed.
   NOTE:  A total lunar occultation card is now included.  If you have access to total lunar occultation predictions, then entering them in a file similar to the included example file will allow one to see each day's occultations.  If you do not have access to these data, then use the "Delete Lunar Card" button.  Delete the field when asked to and all will bw as is was before.
   The dates of maximum ZHR of selected meteor showers are calculated on a separate card.  Olson, Sky & Telescope, 78(2), 195, 1989.
  Jupiter Galilean Satellite Timing Predictions are displayed for the current date.  The file for calendar year 1989 is included.  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