Depends on exactly what type of observation you're doing and how big your telescope is. A lot of telescopes use CCD sensors which are more sensitive but have a

Depends on exactly what type of observation you're doing and how big your telescope is. A lot of telescopes use CCD sensors which are more sensitive but have a bad side effect in that once a pixel saturates it starts to bleed into adjacent pixels causing massive horizontally or vertically oriented blooms that white out a bunch of pixels.