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#1 werewolf6977

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Posted 01 February 2004 - 05:48 PM

Would (could) someone out there explain to me the advantage(s) of an SNT? Or is this just a way for some one in the purchasing dept of the big two to unload the extra 100,000 corrector plate blanks they orderd by mistake? WW

#2 desertstars

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Posted 01 February 2004 - 05:56 PM

Doesn't it have something to do with correcting for the limitations of having a short focal length? :question:

#3 werewolf6977

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Posted 01 February 2004 - 06:02 PM

Beats the "friend" outta me. That's why I asked this dumb question. WW

#4 desertstars

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Posted 01 February 2004 - 06:03 PM

Beats the "friend" outta me. That's why I asked this dumb question. WW


Watch it with the "f" word, there, fella!

Well, with any luck someone more knowledgable will drop by, and then we'll both know.

#5 Suk Lee

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Posted 01 February 2004 - 06:10 PM

Shorter focal length = wider field views.

In typical SNT's, the diagonal is kept small to limit contrast reduction, which means that while they enable wide field views, they'll exhibit light dropoff in the corners for widefield astrophotography.

Suk

#6 jrcrilly

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Posted 01 February 2004 - 08:36 PM

Yes; it's just a variant of a fast Newtonian. Advantages over a straight F/4 Newt include a spherical primary (much easier to figure than an F/4 parabaloid) and reduced coma due to the corrector (which is required anyway). Also there is no secondary spider so no diffraction spikes. Disadvantages include the necessity for a corrector and the increased cost/complexity/light loss it brings.


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