Astronomy Answers: From the Astronomical Dictionary

Astronomy Answers
From the Astronomical Dictionary

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The description of the word you requested from the astronomical dictionary is given below.

the hour angle

The hour angle of a celestial body is the difference in right ascension between that body and the meridian (of right ascension) that is due south at that time. The hour angle is usually measured not in degrees but in hours, minutes, and seconds, just like the right ascension. The hour angle indicates (in sidereal time) how long ago the body was due south.