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Related to Newtonian focus: Cassegrain focus
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I used a Baader MPCC coma corrector at my classical Cassegrain's f/4 Newtonian focus, but found this unnecessary when I used the G3 cameras with my 8-inch f/5 Newtonian.
Like the C150-HD (its smaller sibling), the G8-N has an aberration-reducing lens close to its Newtonian focus.
I tested Nightscape at the f/4 Newtonian focus of my vintage 12(1/2)-inch classical Cassegrain reflector, using a Baader MPCC coma corrector to improve star images at the edges of the field covered by Nightscape's large chip.