I found the following which pastes into a Facebook story without munging the code. These calculations could be done with an inexpensive scientific calculator. They convert observed alt and azimuth to right ascension and declination, or could be used to confirm your position. The URL in the link may be more relavent for navigation Some time ago Tom Crowley furnished equations to determine ALTitude angle and AZimuth for known RA (right ascension), DEClination, and LST (local sidereal time), LONgitude, and LATitude. These equations may be found at en.wikipedia.org/wiki/Altitude_(astronomy)#Elevation_angle and are based on a spherical triangle. The same spherical triangle may be solved for RA and DEC when ALT and AZ are known instead of vice-versa. I do not have Greek letters readily available so I will use all cap multiple English letters instead, except the single letter, H, will be hour angle. Declination, DEC, must be solved first because it is used to find hour angle, H. sin DEC = sin LAT sin ALT + cos LAT cos ALT cos AZ cos H = (sin ALT - sin DEC sin LAT)/(cos DEC cos LAT) The arc cos function may be used to find H. H = LST - RA therefore RA = LST - H The U. S. Naval Observatory website Astronomy Applications department has an on-line calculator for LST and formulae that can be used with a scientific calculator if Web access is not available. Best wishes, Warren
Posted on: Sat, 21 Sep 2013 21:40:02 +0000
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