Quote:
Originally Posted by raymo
Chris, Your 8" Newt was undermounted on an EQ5, need at least an HEQ5.
If your cameras wouldn't focus, you hadn't done your research, and had bought a Newt optimised for visual.[which is to say, most Newts].
You can't beat the laws of Physics, the 200mm has 5x the light gathering power of a 90mm. The secondary reduces light gathering by around 6%,
negligible. Your images may well be as bright, but will not show as much
nebulosity or colour, [for the same length sub],and on objects full of detail such as the moon will not show as fine a detail. Resolution is a function of
aperture, so the finest optics known to man will not allow a 90mm scope to
resolve detail as small as a 200mm will. Horses for courses.
raymo
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Hi Ray, it's been a while.
Firstly, like I said, it was on a NEQ6. The mount was never the issue.
Secondly, totally agree that the larger aperture and faster ratio SHOULD by all accounts - and laws of physics - make for a better exposed image. No argument there. I've been a photographer for years and understand the principles very well. All I'm saying is that in practice it absolutely does not.
Thirdly, both my reflector OTAs are imaging OTAs. One was a brand new GSO, and the other was in fact your very own blue Skywatcher with the motorised focuser. I did indeed do my research - quite a lot of it.
All good. I'm very glad to hear I'm not the only one who decided that refractors are the better option! I now know what my ideal rig is. Time to start saving again...!
Thanks all, appreciate your help.