The most popular telescope system that is used by most amature astronomers is an 8" F/10 Schmidt Cassegrain telescope which incorporates the best qualities and features of both the refractor and the reflector. The 8"F/10 is best also for astro-photography. If you want to become a serious lunar and planetary observer a nice 4 inch refractor may be a good starting system. For deep sky either a 6" or 8" reflecting telescope is a good choice because you get a lot of aperture for low cost. In my opinion the best way to make your selection or gain information is to view through a variety of telescopes at a star party. A good book to help explain telescope differences is "Night Watch" by Terence Dickinson. Hope the information is helpful to you.
