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Old 29-08-2013, 01:02 PM
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Joshua Bunn (Joshua)
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Joshua Bunn is offline
Join Date: Oct 2011
Location: Albany, Western Australia
Posts: 1,093
Originally Posted by Shiraz View Post
looks to me like something is moving in the scope Joshua, which is surprising given how well they appear to be built. the second zenith image definitely shows some collimation offset - Poisson's spot should be central and it looks like it is down and to the left.
If the primary is stable, is it possible that one of the correcting lenses is slightly loose or is there any movement around that assembly? I read that the CDK design is extremely sensitive to positioning/alignment of the corrector lenses. The secondary is spherical, so that should be fairly tolerant of minor shifts.
Thanks Ray,

I would agree with you about the slight movement in the secondary shadow in that image. Yes, the lenses are tight. I made sure the retaining ring was tight less than a week ago and the 1st imaging night after checking them, the elongation was there.I guess it wouldnt hurt to remove them and put them back in just to be sure.

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