View Single Post
  #12  
Old 02-06-2019, 02:51 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 18,183
Smaller scopes are very good at widefield imaging of which there are quite a few wide objects to image. They are generally very bright and you are not trying to get the smallest resolution possible.

Larger aperture scopes can image fainter objects like galaxies, even faint ones if you have a dark site.

So a typical reason to have both smaller aperture refractors of shortish focal length and a longer focal length larger aperture compound scope is to be able to do both types of images.

I don't think that has changed because CMOS cameras are available. But I do see may wonderful CMOS images and those are typically on a 10 inch Newt or something similar like a 200mm RC scope.

Not all CCDs are large pixels either. The popular KAF8300 sensor is 5.45 microns and the popular KAF16200 is 6 microns. A lot of full frame camera sensors have pixel sizes around the 6 micron range.

Greg.
Reply With Quote