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4.10. aard: Horizon to equatorial coordinates

To convert a celestial position in horizon coordinates to the equivalent equatorial coordinates for a given observer's precision, use a command of this form:

aard az±alt lat lon dt

Azimuth of the object, followed by either “+” or “-” sign and altitude. For the syntax of these quantities, see Section 4.2, “Specifying angles on command lines”.

lat lon

Latitude and longitude of the observer; see Section 4.3, “Specifying latitude and longitude on command lines” for their formats.


Date and time of the observation; see Section 4.1, “Specifying dates and times on command lines”.

This example would find the right ascension and declination of a celestial object viewed at an azimuth of 283°16′18″ and an altitude of 19°20′2″, with the observer located at 34°8′42″ N, 107°50′37″ W, on Feb. 29, 2008, at 18:46 Mountain Time.

aard 283d16m18s+19d20m2s 34d08m42sn 107d50m37sw 2008-02-29t18:46mt