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Old 12-07-2011, 10:19 AM
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andrei23 (Andrei)
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Join Date: Jul 2011
Location: Los Angeles, USA
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Question 6" Reflector vs. 90mm Cassegrain?

Hi there,

I unfortunately bought one of those cheapie 76/700mm Optus telescopes at a flea market for $20. Moon looked great, but most nights it was either moon or "dots", so after a couple of sky-gazing attempts I eventually lost interest.

I'm looking to upgrade my set-up with one of those GPS/GoTo/camera "idiot"-proof kits which seem to make astronomy so much more fun for the rest of us, and I think I've got it narrowed down to two scopes in terms of bang for the buck (both are about $650 for the entire kit):

One is a 6" reflector with 1400mm focal length and 140X magnification, 280X with the Barlow adaptor (eBay item # 140545877289). The other is a 90mm Cassegrain with a 1200mm focal length and 155X magnification (eBay item # 130518260467). Obviously the 6" collects more light, but I've been told that due to the Cassegrain's superior optics and shorter focal length that in a rural, low-light setting I may actually get clearer images. Intuition tells me to still go with the 6", as the wider aperture should make much more difference then 200mm of focal length, no?

Or am I better off saving my pennies a bit longer and getting an 8" because neither of these will really be much of an improvement over my 76/700? Only thing with the 8" models is they don't seem to have the auto-everything GPS & camera kits, not for under $2000 anyway. Is it really 4X "more scope", or can I find some amateur amusement also with a 6"?

Really appreciate the input of more experienced members - thanks in advance!
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