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Duncan Mask Collimation Questions

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#1 Ed Wiley

Ed Wiley

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Posted 19 January 2013 - 12:08 PM

I recently acquired a C-11 HD. My previous experience with SCTs was a Meade 8" and I did the usual collimation routines. I have been reading about using a Duncan Mask for collimation and have a couple of questions for anyone who has used one.

1. Good, bad, indifferent relative to normal collimation routines?
2. If you use one do you fit it to the end of the optical tube or inside on the shelf ring of the corrector plate?

Many thanks,
Ed

#2 Steve OK

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Posted 19 January 2013 - 01:32 PM

Hey, Ed. I've used a Duncan mask with my C11, and found it to be useful. Since the three openings in the mask can be aligned with the three collimation screws, you can get an unambiguous indication of which screw to turn, and whether you've gone too far or not far enough. I found the mask to be particularly helpful when trying to collimate in less-than-perfect seeing, but as with any collimation attempt it is easier in good seeing. I cut mine to fit over the secondary housing, and onto the corrector retaining ring, but it would work either way. As easy as one is to cut out, it is worth a try!

Steve

#3 Ed Wiley

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Posted 19 January 2013 - 05:47 PM

Thanks, Steve. I actually have a couple of prototypes, one cut for the corrector ring set-up and another for the end of the tube. As soon as my mount returns I will be very interested in seeing how they work.

Your input much appreciated,

Ed






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