I wasn't aware of a new reducer aside from the one designated for Edge scopes. The one I am using is an old used one that I got with a box full of goodies.
But EdZ goes on to say that he wouldn't hesitate to use the 2 inch diagonal in combination with a reducer.
Now who am I to side with Greg? EdZ or yourself?
And if not $7000, how much are these 92mm apos, that you mention so frequently as a part of your SCT setups (and a reason not to use 2 inch eyepieces in conjunction with a reducer), ... how much are these going for these days? Wasn't one of those a Stowaway?
Also, from my experience using the 1.8 degree field of view, for not just finding but also viewing, if there are stars that are dimmed at the edge, they are generally not bright stars. As the brighter stars, and even semi-bright stars, do not show noticeable dimming to my eye.
The top tier triplet 92mm apos (which as far as I know can't even be bought new at this point) were running, before COVID, at $3.5k and change depending on accessories.
I have seen the AT92 triplet in action, it is owned by a friend. It is also quite popular here on CN and costs considerably less than the "bespoke" brands:
So that's half the price.
There are 80mm scopes of good optical quality that go for less than $1k. I used an 80mm for a while.
I'm not sure I would recommend top-mounting a refractor for you. You mentioned you were using bungee cords instead of a counterweight system. There would be the refractor scope, some kind of dovetail to go on the c8, some kind of ring or other attachment system for the dovetail to the refractor. When I first ventured in this direction, it posed a lot of challenges that were expensive to resolve. For the C14 I had to upgrade from the G11 to another mount. The G11 got demoted from C14 duty to carrying refractors and the c8 (together or singly).
In other words if you put a ten to fifteen pound load on top of your c8/mount your current mounting system could become unworkable. That's basically what happened to me. I added a four inch refractor to a C14 and it was getting bouncy in a way that I didn't like. If someone had a super polaris and was using a c8 (I used a c8 that way) and wanted to put a three inch refractor on it, that wouldn't work. (You could use the 3 inch refractor by itself to good effect)
When I recommend two-scope viewing I usually attempt to recommend a refractor sized to the rig. In some cases that is 70 or 80mm. I lack the coordination and risk inclination to mount a 5" or larger refractor on or on a dual saddle mount with an SCT. Better people than me have pulled it off.
As for the budget the user base of the forums is all over the map. I spend about $2k a year on astro gear, or at least I used to. I can't think of anything else to buy that I'm interested in. And on top of it the kid's in college and it's a $$$ black hole.
But the discrepancies in budgets are part of the life of the forums. You see refractor threads for $3k and even $30k options and you see refractor threads for $300 options including mounts.
If I see someone using a CPC 8" though I infer they are not in the hobby on a rock bottom budget basis and might be willing to explore a two scope set-up. People who are really budget constrained typically are using 8" solid tube Dobs.
Back in the day when I was using a Super Polaris + c8 (Celestron sold them that way) I didn't have a refractor. I did have an f/6.3 reducer corrector which I got the same way you did: in a bunch of stuff in a box and a "hmmm what's this." (I sold that reducer corrector but it is the way of the world, another box of stuff showed up and there was another f/6.3 reducer corrector. For all I know it was the same one I sold!) I pretty quickly concluded it wasn't for me and that the c8 is not really a wide field scope. A couple years later I had a second mount and set up a refractor next to the SCT. This was a lot of fun but it was also a lot of work. I had to find every object twice. And I had two set ups and two break downs and two power supplies and everything else. It was then that the light bulb went off and I began to look hard at how people were putting refractors on SCTs.
It wasn't a new practice. You can see pictures of refractors mounted on top of Newtonians in a 1965 Optical Craftsman catalog. When I was a kid I never understood why one would do that. As an adult I still don't understand why they did that. I guess for guiding. In the age of the Kellner it's not as if they were getting huge wide fields off their f/12 to f/15 refractors.
Some our eminent authorities in this forum recommended the f/6.3 reducer in general use as field flattener and as a way to economize on eyepieces (the Barlow lets 15 to 30mm eyepieces pretend to be 7 to 15mm eyepieces, the RC lets 15 to 30mm eyepieces pretend to be upper 20mm and 30-40 mm eyepieces). I did use it for a while on that premise. But I thought the views were better in dedicated eyepieces and moved in that direction. (using Russell and Rini wide fields, in the beginning) So yes: Using the r/c with a two inch diagonal. I have a twofold dislike of the system. 1. It does not really give a wide field view with the 30 to 40mm wide fields. Not a good (unvignetted one) anyhow. 2. I just don't like it generally. You have to screw it on. If you're looking at a planet and you want more magnification you have to "overcome" the negative effect of the RC by using shorter fl eyepieces or barlows. It makes no sense to me to barlow a scope with an RC to take a gander at Mars, for example. I also don't particularly like the visual effect and reduced sky contrast of the lower power views that come out of the RC.
In this matter I have disagreed with virtually everyone (and there are quite a few) who like to say that (when the topic comes up in a refractor forum etc) that an SCT can give a wide field as a visual scope. The SCT really doesn't compete there. I push hard on the matter because I think it's an error and gives people the wrong idea of the product.
Given some of the points you have made about your rig (very light weight mount) and use habits (apparently in the back yard, which I can't do) I wouldn't recommend the kind of rig I use or an up-top refractor.* I drive 30 miles to a remote site. It's an expedition. We leave early so we can stop for tuna sandwich from the convenience store, and as the sun sets I do the rituals of setting up. I enjoy the gear and working with it.
It's also the case that a person should really only pursue a top mounted refractor if the skies are dark enough to let the open clusters pop. Absent that, the game is not worth the candle.
*you might get good use out of a stellarvue 50mm 9x50 which can take regular 1.25" eyepieces. The weight penalty would not be huge. I saw NGC 5053 (9th mag glob) in this scope!
Edited by gnowellsct, 23 June 2022 - 02:20 PM.