1. The problem statement, all variables and given/known data I am asked to draw the ray diagram for an incident plane wave whose rays are at an angle α with respect to the optical axis of the telescope. I have done this, but I need to find an expression for the angle between the outgoing rays and the optical axis, in terms of f1, f2, and α . f1 is the focal length for the converging lens and f2 is the focal length for the diverging lens 2. Relevant equations 3. The attempt at a solution I know that generally the magnification would be (-) f1/f2. I am wondering how the angle α will affect this. As to the actual question at hand, I am unsure how to proceed. I believe that the rays are not outgoing at an angle of α, but otherwise I am unsure.