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Orion CLAN clear aperature Newtonian 3.6"

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#1 BigC

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Posted 31 July 2011 - 11:02 AM


3.6" unobstructed reflector by Orion;supposed to have US-made asymetrical mirror.Conrast supposedly good as refractor without CA.Anyone have one? Know where to get one?Experience?

Just stumbled across the description online,never heard of it before!Found two old webpages ,one priced in euros,on at Australian$ 3000!!!

#2 idealistic

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Posted 31 July 2011 - 01:37 PM

Sounds like a lot of money for a 3.6" scope. What is it an off axis newt? Thats a clever design.

Ive gotta ask, whats a dog polisher?

#3 Roy McCoy

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Posted 31 July 2011 - 01:49 PM

DGM Optics

I believe it began here.

Regards,

#4 BigC

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Posted 31 July 2011 - 03:26 PM

The idea of an affordable modest sized scope with neither diffraction spikes nor CA sounds attractive.But maybe it never caught on in the mass-market scopes?Or marketing such a scope would hurt sales of the others?The search sites suggested ebay and amazon but none were found either place.

I'm not really sure about the dog polisher;it is just something that was said about my buying habits versus a co-worker.Perhaps the person was referring to the electric shoe polishers?At one time some people called their feet "dogs"mdon't know why.Now you know as much about it as I do!!! :)

#5 HellsKitchen

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Posted 31 July 2011 - 07:26 PM

Clever design, but $3000 will buy an XX14 or a 10" premium dob, or even a 4" apo ;)

#6 Jon Isaacs

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Posted 01 August 2011 - 04:33 AM

The idea of an affordable modest sized scope with neither diffraction spikes nor CA sounds attractive.But maybe it never caught on in the mass-market scopes?Or marketing such a scope would hurt sales of the others?The search sites suggested ebay and amazon but none were found either place.

I'm not really sure about the dog polisher;it is just something that was said about my buying habits versus a co-worker.Perhaps the person was referring to the electric shoe polishers?At one time some people called their feet "dogs"mdon't know why.Now you know as much about it as I do!!! :)


The Orion 3.6inch OA was marketed in a small window after the introduction of the ED-80 and before the introduction of the ED-100. It's initial price was about $700 and the focal ratio was about 13 or so, resulting in a tube that was as long and about the same diameter as a 6 inch F/8 Newtonian.

They never sold well and they kept dropping the price until I believe one could buy one for about $200. The advantage of the OA Newtonian is that it has no central obstruction, that makes it attractive to those enamored with refractors. However it is not all peaches and cream. The focal ratios are necessarily long because the primary mirror is actually a section of a much faster Parabolic mirror, the common OA is F/11 and that is cut from an F/4 primary. So while the focal ratio is F/11, there are coma-like off-axis aberrations that are associated with the OA section of that F/4 mirror. Dan Mcshane of DGM said they were about like one would expect with a F/6-F/7 Newtonian.

If you look at diffraction and the trade off in contrast between a 6 inch F/8 with a 20% CO and a 3.6 inch unobstructed telescope, it's pretty clear that the 6 inch F/8 has the advantage... i.e. the energy in the airy disk structure is more concentrated...


It is also worth noting that the primary mirror is cut from a much larger mirror, that 3.6inch was probably cut from maybe a 10 inch F/5. Cost wise that is reasonable but when one starts looking at larger OA scopes, the optics start to get expensive... A 16 inch F/4 might provide four 6 inch mirrors..

These days, with used ED-80s going for $300 and ED-100s going for $400 a 3.6 OA that is the size of an 6 inch F/8 Newtonian would seem to be a hard sell..

If one wants an unobstructed scope, to me, the OA design makes more sense as 6 inch or larger scope, 6 inch apos are very expensive so the OA design can compete more effectively as a lower priced alternative. On the other hand... a larger Newtonian always makes viable alternative so the market is small.

That's my two cents.

Jon

#7 Binojunky

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Posted 01 August 2011 - 09:25 AM

Sky & Telescope reviewed this scope, it was in the same tube as the standard 6" dob , not to bore you with the details they said more or less that the standard 6" showed more though with difraction spikes, the 3.6" is no longer in production, dave.


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