Physics-Aberration

In optics an aberration is a defect in an image caused by a lens or a mirror. There are two main types of aberrations  one is chromatic aberration the other is spherical aberration. Chromatic aberration can only be caused by a lens, and has the effect of causing different colors to be refracted by the lens. This is normally caused by variations in the n, or the index of the refractive of material, indicating a nonuniform substance.

Spherical aberration on the other hand is when the light from an object focus in slightly different positions due to defects in the thickness or curvature of the lens. This means that there isn't a clear way to find the image of an object viewed with this lens as there is no convergence point.

This term can also be applied to astrophysics. It refers to the phenomenon where the position of a celestial body is displaced in relation to its actual position due to the movement of the earth. This can be correctly simply as we can approximate this effect using the sin(θ) = θ approximation, giving us an angular displacement of v/c where v is equal to the earth's orbital velocity and c is the speed of light.