The angular motion of a star across the celestial sphere is a measure of its
A) radial velocity.
B) axial velocity.
C) total velocity.
D) proper motion.

Question

Quizplus · Accepted Answer

The angular motion of a star across the celestial sphere is measured as its proper motion, which reflects its movement relative to the celestial sphere from the perspective of an observer on Earth.

The Angular Motion of a Star Across the Celestial Sphere