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Old 17-01-2024, 01:37 AM
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AlexN
Widefield wuss

AlexN is offline
 
Join Date: Mar 2008
Location: Caboolture, Australia
Posts: 6,855
I had an EXTREMELY high quality mak cass a long time ago, an Intes Micro 715. 7.1" f/15 2700mm F/L. Planetary and lunar views were phenomenal. Better than my C11. More "refractor like" with very strong contrast, the scope beautifully snapped into focus, and it was built incredibly, incredibly well.

I tested it with an APS-C sensor and a couple of much smaller sensors, like the Sbig st8-xmei, st-10xe, st-9xme etc, and the scope could only produce an acceptable image on the st9, sensor, which, if you're old enough to remember, was a 512px × 512px square sensor with gargantuan 20um pixels. The st8 was flat except the edges (where it was wider than the st9, however with its 9um pixels, the pixel scale was unwieldy. The st10 was sensitive enough to work well at f/15, however, it's sensor was bigger than the st8, and 6.8um pixels made it VERY sensitive to guiding issues. I ran that with adaptive optics to try to respond faster to inaccuracies in tracking, which worked well, but again, the field curvature was fairly extreme. At least 50% of the image was murky muddy blurs.

The qhy8 had no chance. The sensor was 4x that of the st10, so your target would be in the middle with a star trek like warp drive effect at the edges... 7.4um pixels and no adaptive optics option meant I was guiding with my st80, a 400mm guide scope is no match for a 2700mm imager...

In my experience, I'd say forget the mak cass. A mak newt however. That is a special scope and if you can get one at a reasonable price, I can't imagine any reason not too. Absolutely brilliant scopes.
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