The astronomical telescope is used to observe district images of heavenly bodies like stars, planets etc. It is two lens system first one is an objective lens which has a large aperture and large focal length because it forms the image of a distant object at its focal length, and the second one is the eyepiece, which behaves as a simple magnifier with which to see the image formed by the objective.

The astronomical telescope is quite heavy and bulky. Aberration is a property of optical systems like  lenses that makes light to be spread out over a region of space rather than focused to a point. This consists of lenses so, it will suffer spherical and chromatic aberration.