RISE-SET.DOC

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RISE-SET.BAS IS A MBASIC PROGRAM TO CALCULATE THE AZMUTH AND
LOCAL HOUR ANGLE OF THE RISE AND SET OF ASTRONOMICAL BODIES
THE ALTITUDE OF UPPER CULMINATION (TRANSIT) OF THOSE BODIES WHICH
DO ACTUALLY RISE AND THE DIRECTION FROM ZENITH OF TRANSIT.
IT WAS WRITTEN BY MIKE FINERTY APRIL 18, 1985, USING FORMULAE
FROM SMART'S TEXTBOOK ON SPHERICAL ASTRONOMY, AND A LITTLE OF HIS
OWN RECCONING.
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THE PROGRAM WILL RETURN A "Illegal function call" ERROR IF THE
ASTRONOMICAL BODY IN QUESTION DOES NOT RISE OR DOES NOT SET, THAT
IS IF THE BODY IS IN THE CIRCUMPOLAR REGION AND IS ALWAYS ABOVE
THE HORIZON OR ALWAYS BELOW THE HORIZON, THE INTERSECTION OF ITS
PATH WITH THE HORIZON IS "IMMAGINARY" AND THE SOLUTION REQUIRES
THE USE OF COMPLEX NUMBERS (WHICH MBASIC DOESN'T LIKE), SO IT
RETURNS AN ERROR MESSAGE. I LABORED IN VAIN TO HAVE IT RETURN A
MORE MEANINGFUL ERROR MESSAGE, BUT IT APPEARS THAT WE ARE STUCK
WITH "Illegal function call." AFTER ALL. MIKE FINERTY, TUCSON.
APRIL 18, 1985.