Quote:
Originally Posted by ariefm71
John, I think what makes Tak Cassegrains great (apart from the 1/20th wave optics)
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Firstly that is subjective because we don't know how the optical quality is tested. Is it 1/20th wave RMS, 1/20th wave Peak to Valley, or 1/20th wave at the wavefront? However, we do know that TAK optics are excellent irrespective of the numbers, so you don't need to quote them. It's all pretty academic anyway because the skill of the observer and seeing conditions make optics better than about 1/10th wave at the wavefront superfluous. Just for the record my 14" SDM has a 1/40th wave Zambuto primary and a 1/30th wave Protostar Quartz secondary. My 10" SDM with Suchting primary has optics that match the 14".
Quote:
Originally Posted by ariefm71
I still think the Tak will have an advantage over newtonian due to this, unless you observe from a very dark location.
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If that's the case you have found a way to defy some of the basic laws of physics. See my previous post. The Mewlons are very good, there is no doubting that, but they still come up fractionally short of a well set up premium Newtonian due to the large central obstruction and the other factors I mentioned. They are IMO a better visual platform than an equal aperture SCT.
Cheers,
John B