Quote:
Originally Posted by Wavytone
Hi Jethro.
SCTs are cheap, especially used ones. The starting point for beginners is an 8" or if you are serious a C9.25 or C11. Optically, Celestrons on average tend to be a tad better than Meades (Meade 10" or 12") and the Meade focusser mechanism can be very sloppy.
For maks... the choices come down to:
a) Questar 3.5", small, built like a jewel and if money is no object, a Questar 7";
b) Skywatcher f/15 Maksutovs, the 150 or particularly the 180mm, these are bargains compared to Questar, optically most are 9 to 9.5 put of 10, however the downside is you need a decent mount (extra $);
c) Look for a secondhand Intes Maksutov, ideally an M715 or M815, the optics are superb. They are rare but occasionally you can find one on Astromart, if so pounce on it. The point being Intes guaranteed PTV 1/6 wave for the whole scope and for the deluxe models (-D suffix) 1/8 wave, ostensibly perfect.
d) Then there are the dream scopes - the big maks starting with my Santel MK91, and the ones from TEC, AP or APM - 10" all the way to 16. If you have really, really deep pockets. LZOS were ordered to stop production and the last one has been sold by APM but one or two have resurfaced recently on Astromart. But take a very deep breath when you look at the price, these are well into 4 digits. OTOH when you look at the price and size of say a 7" f/10 triplet APO... you can see why people buy a large Mak.
Why, ? Well there really is a difference. A good friend (and an ex-SCT user - having tried several) now has an Intes M715D that will easily slay any 8" - 9" SCT for resolution on the planets. Then there is my MK91 which will put a C11 to shame.
The MK91 is pure russian unobtainium however, with just 28 made and mine is the only one in Oz. I know of 3 others internationally, and their owners won't part with them.
Lastly there is another option - planetary exotica such as a large schiefspiegler. I recall the 12" f/23 Barry Adcock built in Victoria and the planetary images from that were stunning.
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I believe some of your suggestions may be above his recommended budget
