Some of the security cameras or cameras refitted specifically for astronomy give the user manual control over exposure length and gain functions. Thus, I consider some method of exposure control to be fairly important for astronomy imaging. No, most people using a surveillance camera couple the camera directly to the telescope. Almost any telescope will do, though one that has a tracking motor makes imaging easier. As the video chip generally covers a very small field of view, it will be necessary to constantly adjust the telescope to keep it on target.
Larger telescopes have an advantage as well.
Their greater light gathering ability will allow for more magnification and during a night of excellent seeing and quality optics, superior resolution. If you are using a refractor that is not an APO, using a green filter may help to minimize the chromatic aberration. Some wavelengths are less effected by atmospheric distortion that others. A red or infrared filter may help. Red can also be used to improve contrast.