|
Selection depends on use. Wide field guide scopes are easier to guide with as they are usually quite a fast instrument (low focal ratio). As such the camera doesn't need to be too sensitive. Also a generous FoV makes locating a bright guide star simple.
The opposite can be said for guide cameras operating through an OAG. Much smaller field of view and by nature the pick off prism is typically at the edge of the telescope's optical path where there is a drop off in intensity of light. In such circumstances, camera sensitivity is important.
Of course you can always 2x2 bin if the camera supports it to boost sensitivity in both situations, providing the arcsec/pixel combination works out comparing the main imaging system.
I'm in awe how many guiders are available on the market today. 'Once upon a time' there was the ST-4, which revolutionised long exposure imaging. Look now and you can guide with just about any video or imaging capture device if there's an ASCOM driver for it.
|