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2" Focuser

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Posted by Jeff on May 24, 2002 18:59:41 UTC

Thanks.I found a program that helped me understand things a little better.(NEWT)It has given me some funny readings on occassion so i'm not sure how accurate it is.
I was going for wide views.And now I guess I have to decide between 2 secondary sizes.If NEWT is calculating correctly,a 1.52" secondary will give me 75% illumination across 2 degrees(rounded up),while a 1.83" will give me 75% illumination across 2.6 degrees.My 27mm panoptic will give me a 2.4 degree field of view with this scope.
According to the helpfiles in NEWT,the light drops off sharply past the 75% area,so do you think I should assume that a 1.52 secondary will give me vingetting in the wide field panoptic?That is my main concern...being able to use my 2" eyepiece without any noticable vignetting,but I also want to keep the secondary as small as I can.
thanks again

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