Calculation of right ascension and declination from azimuth, elevation, latitude, date and time This is something what I did when I just turned 16 years old,  ☞ it took me a few days to figure it out but finally I came up with a formula. And now a few decades later it's time to check if the formula is correct ;) So here with a script in this web page I implemented the formula and from some sample data I found on the web it seems the formula works :) Input: azimuth (0..360): ° elevation (0..90): ° latitude (-90..90): ° days since vernal equinox ~March 21 (0..365.25): d local time: (0..24): (sun in south at 12:00) h Output: right ascension: ° declination: °

Test - comparison with data I found on the web:
An observer O at geogr. latitude beta=50° N and longitude 10° E, on 1991/05/19 at 13:00 UT,
will see a star of right ascension RA=55.8° and declination delta=19.7°
at azimuth az=43.6° and altitude h=53.4°
Source: http://www.geoastro.de/elevaz/basics/index.htm