When choosing a telescope you will inevitably be faced with the dilemma of whether to buy a reflector or a refractor type telescope. Much has been written on the subject and here are some of the pros and cons of each to help you decide:
Reflector telescopes use mirrors and are usually short and wide in appearance. They are the instrument of choice for deep space and wide field viewing on account of their large apertures and superior light gathering abilities. This makes them ideal for viewing such deep-sky objects (DOSs) as nebulae, star clusters and galaxies . Other pluses for reflectors are that they are far cheaper to buy than refractors, are more portable, and their mirrors reflect all wavelengths of light the same thus correcting for any chromatic aberration. A good entry level for amateur astronomers would be a 4 inch (100mm) reflector.
Refractor Telescope use lenses and are usually long and slim in appearance. They are ideal for viewing larger, brighter objects such as the Moon and planets. Pluses for refractor telescopes include “right-side-up” images, the ability to come to thermal stability quickly meaning low image distortion, and a sealed tube which means little maintenance is required. On the other hand, refractor telescopes can suffer from some chromatic aberration caused by using lenses, and they are generally more expensive to buy than reflectors. A good entry level for amateur astronomers would be a 80 mm (3.1 inches) or more reflector.
A compromise between these two types of telescopes is a hybrid telescope known as a catadioptric, which uses both lenses and mirrors, and are excellent for observing the moon, planets and binary stars, as well as deep-sky objects. This hybrid telescope comes in two main varieties known as either Schmidt or Makutsov after their designers. They are durable, highly portable, easy to use and produce “right-side-up” images. In addition to combining the best qualities of both reflectors and refractors into one package, the price of a catadioptric telescopes usually falls mid way between that of a refractor and reflector.