This started out as a quick comment, but it kinda got a bit more complex ... so bear with me.
There's no question that in order to get a well corrected relatively large imaging circle at the really fast f2 requires some good glass and that usually means a pretty good dent in the pocket book. As do larger sensor cameras.
I think however that we've been doing some folks a disservice by suggesting the need for more expensive options without continuing to promote gear that is more accessible to those without big budgets. The push to larger sensors is very enticing, we all want larger fovs ... but it brings with it a substantial increase in costs from a whole variety of areas.
We've talked extensively about focal reducers and the costs of going faster than .5x with larger imaging circles but there's also the impact of things like substantially bigger images on stacking and other image processing tools ... requiring more and more computer processing and throughput (and more costs).
I'm not suggesting any sort of problem with continuing to demonstrate and explore these larger sensor options ... quite the opposite, I like most love to read about new more capable gear. It's just that I think we also need to continue to promote more of the more affordable gear.
Those GSO imaging Newtonians have generally garnered very good reviews and have demonstrated very capable imaging characteristics at f4.4. Does the coma corrector create the same quality field as say an EdgeHD scope ... nope, but it does seem to produce fields as good or better than what we've seen with SCTs using the better examples of the inexpensive .5x focal reducers with smaller sensor cameras.
I don't mean to promote the GSO products per se, but I don't think they should be so quickly discounted out of hand. I don't own one but I've looked through a few and talked to some other owners who've been quite impressed with the quality for imaging. No, we're not talking Takahashi quality for a few hundred dollars but the optical qualities do seem to be comparable to what many folks are currently demonstrating with many SCTs and achromat/ED refractors.
We've got lower (or no) cost software that allows us to use low cost alt az mounts for EAA. We've got low cost entry level camera packages and a lot more choices in the mid priced categories. What we need are more proven low cost scopes and mounts suitable for EAA (faster than f5 and able to effectively cover up to at least type 2/3" sensors). There are lots of possibilities, we just need more folks to demonstrate how effective various low cost scope configurations are ... alongside the wonderful examples from Hyperstar based SCTs, RASAs and the like.
Edited by mclewis1, 12 April 2016 - 03:26 PM.