Astronomical Aberration is a well known physical phenomenon dealing with light and the apparent position of objects.
When observed from the Earth, light from the Sun or any other astronomical object shows astronomical aberration. For the Sun, it is known that light takes about 8.3 minutes to come to the Earth. While the light is traveling, the Earth is revolving around the Sun, and so the Sun appears to move through an angle of about 20 arc seconds[?]. Therefore, the light is actually showing where the Sun was 8.3 minutes ago. The actual instantaneous position of the Sun differs from its apparent position by about 20". We will see the Sun in its true present position about 8.3 minutes into the future (which is how long it takes for the light to reach our eyes).
This phenomenon is also true for stars. Their positions are displaced from their average position by up to 20", the variation is actually dependent upon the Earth's motion around the Sun, the star's motion relative to the Sun, and also its relative direction from our vantage point.
This article should be merged with Aberration of light
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