I do most of my astro-imaging with a monochrome CCD camera that lets me use a variety of filters.  This provides the best image quality and flexibility, but there are 2 significant drawbacks:  First, because of the expense of these specialty cameras, I can only afford one with a fairly small sensor (the same size as digital cameras using the “four thirds” format, which is smaller than the typical APS-sized DSLR).  Second, capturing a color image takes much longer because you have to take separate red, green, and blue exposures (and sometimes luminance exposures as well).  Processing these separate exposures […]