Types of Telescopes. Pros, and Cons of Reflectors, Refractors, and Catadioptrics – Night Sky Gazing
How often do Cassegrain types of telescopes need to be collimated, or under what circumstances (eg. after being carried in the car, shaking, dropping, etc)? - Quora
vik dhillon: phy217 - catadioptric telescopes
Reflector vs Refractor Telescopes: Which is better?
Black list of telescopes. Bad telescopes not for beginner
What is a catadioptric telescope used for? - Quora