>>>Jon:
I've got the worlds (actually Rod now recommends picking one up in his used gudie) only "very good" C90 which is my travel scope. I've got the LAR and use a Lumicon 1.25" diagonal and the views are as good as any ETX I've seen (remember a C9o @ 1000mm has a much wider FOV) and quite a lot cleaner than the G185 I had (don't you have one of those also?).
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I do and I have had some good times with it, I also have a Pronto which is physically larger but gives superior views, especially with 2 inch eyepieces. 5 degree FOV are possible.
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I use it with my focal reducer and have a f6.3 scope that with a 32mm plossl gives extremely wide views in a scope that fits under the airline seat with 4 ep, barlow, whitelight sun filter, Red LED light, my PDA with PockeySky.
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A C5 also fits nicely under the airline seat and has substantially greater aperture which makes viewing DSOs quite nice. But I would think that C-90s must show substantial vignetting with a Focal Reducer and a 32 mm eyepiece or some such thing., or so it would seem, the hole is the back is just not that big...
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Taken it to Mexico, Az., Hawaii, and on every driving trip my wife and I take. Also it is a great digiscope for my Nikon CP4500. So I just can part with it. Thats also why the 1278 fit my scope stable.
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I have the Orion/Synta 120 mm F8.3 scope which should be quite similar to the BO 1278. It does a good job on double stars but the OTA is 40 inches long or so, not airline portable and my 8 inch XT-8 is a better overall performer because of the increase aperture. Thats why it is for sale, just don't use it.
I order the 1026 because I was thinking that the 102mm objective would provide brighter widefield views than my Pronto but still be reasonably small. My guess is that it should be comparable to the C-5 in many ways but probably give those refractor views that don't always happen with Reflectors.
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>>BTW do you have a focal reducer for you C5, you will like what it does for a SCT. except for planets I never use my C8 without it.
I have one, it brings the focal length down to 800mm. Which is essentially one eyepiece step. Nice for Widefield viewing but then when I want to use some magnification, then it requires a barlow. With a smaller aperture, I try to avoid getting too much glass in the optical path. With a C-5, focal reducer, and barlow, there the corrector, the primary, secondary, a couple of pieces of glass in the focal reducer, about 3 in the barlow and then the diagonal, this all preceeds the eyepiece.
Jon
jon