Most expensive per inch of aperature. Best views of planets, moons and sunspots. Direct view of astronomical objects Prone to chromatic abberation Reflector Least expensive per inch of aperature. Works best with an alt-az mount. A good all-around telescope.
Some models require accurate colimation.
Very compact Works well with an Equatorial Mount Best for astrophotography. Very simple and sturdy. Requires hand guiding to follow an object. Must be aligned with Polaris to work. More expensive and not as sturdy.