Free Web Tool · Geodetic Surveying

Astronomical Azimuth

Compute azimuth of the line to the celestial body from observed altitude h, declination δ, and observer latitude φ — hour-angle method (sin az = −cos δ · sin t / cos h).

Input

Local sidereal time minus RA

Results

Hour angle t (deg)—
sin(altitude h)—
Altitude h—
Azimuth from N (deg)—
Method

sin h = sin φ · sin δ + cos φ · cos δ · cos t. sin Az = −cos δ · sin t / cos h. Azimuth measured from North clockwise. If body is east of meridian, Az = computed angle; if west, Az = 360° − computed angle. Use this for sun and Polaris observations after correcting t = LST − RA.