The celestial line produced by the Earth's rotation is described as the line of right ascension. The line of right ascension is one of two lines used by astronomers to find and map specific stars. The second line is the line of declination.
The line of right ascension is considered to be the celestial version of the line of longitude. The position of specific stars is measured in hours and minutes from the right ascension. Since the position of the stars shifts very slowly in response to changes in the direction of the Earth's axis, celestial maps are charted in specific intervals, referred to as epochs.