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Old 02-11-2020, 07:58 AM
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madbadgalaxyman (Robert)
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Join Date: Mar 2011
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Would folding a Newtonian work?

Hey, you ATMs and Optics Gurus,
would folding the light path of a Newtonian work?

While doing this may not have that much impact on the weight of the optical tube assembly, it would put the focus of a Really Really Big Instrument at a much more convenient height, thus saving us from having to perch precariously on a ladder!

There have been various attempts to do this:

https://www.cloudynights.com/topic/4...of-telescopes/

https://www.cloudynights.com/topic/112172-folded-newt/

http://www.jimsmobile.com/buy_ntt40.htm

https://www.cloudynights.com/topic/3...ded-newtonian/

https://www.johanneswilm.org/mike/telescope/


While a lot of attempts to fold the light path of a telescope (including by the Cassegrain-type route) do result in an unacceptably large central obstruction (at least for the optics purists) , I put it to you that what we are looking for in the biggest apertures is essentially a Supergiant(!) Light Bucket for deep sky viewing......
where - in very practical terms (for the Actual Observer) - the central obstruction interferes much less with contrast and resolution than it does during planetary viewing.

But can anyone think of a better way to accomplish the folding of the light path than these designs?

cheers, madbadgalaxyman
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