How do the alt-azimuth coordinates of a star compare with the R.A., Dec. coordinates of that same star?
A) Both sets of coordinates change over the course of a single night.
B) The R.A. and Dec. coordinates change over the course of a single night, but the alt-azimuth coordinates do not.
C) The alt-azimuth coordinates change over the course of a single night, but the R.A. and Dec. coordinates do not.
D) Neither set of coordinates changes over the course of a single night.

Question

Quizplus · Accepted Answer

The alt-azimuth coordinates of a star change throughout the night because they are based on the observer's local horizon, with altitude indicating how high the star is in the sky and azimuth indicating its direction. The R.A. (Right Ascension) and Dec. (Declination) coordinates, however, are fixed on the celestial sphere and do not change over the course of a single night.

How Do the Alt-Azimuth Coordinates of a Star Compare with the R.A