proper motion
Sign in to saveastronomical measure of the observed changes in the apparent places of stars in the sky
AI overview
Proper motion is the measure of how fast a star appears to move across the sky from our perspective on Earth. Tracking this motion helps astronomers understand how stars are actually traveling through space and where they might be headed.
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Article
Relation between proper motion and velocity components of an object.A year ago the object was d units of distance from the Sun, and its light moved in a year by angle μ radian/s. If there has been no distortion by gravitational lensing or otherwise then μ =
v