I recently purchased one of the TS Boren-Simon "PowerNewts". Its very fast and is my first reflector, the first telescope I've ever collimated.
Other carbon fiber Newts sold by TS include the Photon series, the ONC series, and the ONTC series The order of price/quality is Photon < ONC < ONTC. I don't know all the differences, but the ONTC has extra holes drilled in the tube so that the front (secondary) mirror can be moved forward or backwards, which apparently provides an extra touch of optimization depending on whether you are doing photography or visual and whether you are using a reducing coma corrector or not. I believe the ONC comes with a standard focuser, whereas the ONTC price does not include the focuser and you pick from a list of several premium ones and add that to the price.
The Boren-Simon "PowerNewt" appears to be essentially an F4 ONC that comes standard with a 0.75 ASA reducing corrector instead of a non-reducing one, making it effectively F2.8. I bought this scope because I was tired of staying up all night with my F6 telescope doing astrophotography and finding I still had underexposed pics after 8 hours of data collection. I don't have experience with a lot of telescopes, but so far I am happy with this one.
I believe the 0.75 ASA corrector reducer is compatible with the ONTC Newtonians as well, so for example if you bought an F4 ONTC and the ASA corrector, you'd have sort of a high end "PowerNewt" at F2.8. It may also be possible to use the reducer-corrector with the F5 ONTC as well, so then if you had both the reducing corrector and a non-reducing one, you'd be able to choose between F5 and F3.75. But I'd ask and not assume that.
If you are a perfectionist, its probably important to note that the ASA 0.75x reducer-corrector does not correct all the way to the edges of an APS-C sensor (the size in a typical Canon DSLR)
As for collimation: I have never collimated a telescope before and was very nervous about this myself. I decided to buy a non-reducing coma corrector to complement the reducing one that comes with the scope because I was worried about collimation, especially at F2.8.
So far, collimation has not been much of a problem. I bought a nice FarPoint laser collimator and chesire, and followed the instructions that came with them. It took all of about 10 minutes the first time I did it. I check it when I go out to a dark site and sometimes spend 5 minutes giving it a quick tweek.
The hard part is not collimation (which gets the stars in the middle of your field of view to be round), but getting the spacing between the camera sensor and the corrector right so that the stars in the corners of your picture are round too. Once you figure out the right spacer, you're done for all time, but it does actually require you to go out and take pictures and repeatedly take the camera off and on the OTA while you iterate. Mine has an otherwise imperceptible tilt of the focuser so that one corner always has a few stars that are just a bit oval. There are ways to fix this but so far I haven't bothered because its not noticeable unless I enlarge the picture specifically to look for that.
The spacing part is harder at F2.8 than it is at F4, and its probably easier yet at F5. Mostly I've been working at F4 so far. Its still new and I just haven't been able to get it out that many times to both take pictures and deal with the spacer issues on two different correctors.
I think it depends on what you want. I get out about 2 nights a month, and am thrilled to be able to get a pretty good picture in 2 hours at F4 and probably in an hour when I get the spacing correctly set for the reducing adapter. But I'm not a pixel peeper and its not likely that I'm even going to worry about a few stars in the corners that appear oval when I enlarge the picture 10x.
Some people hate the diffraction spikes that Newtonians produce. Its kind of an individual thing. I'm very happy.
Edited by John Tucker, 20 September 2019 - 10:01 PM.