Ed and I were imaging the Pacman Nebula at TDS on 18 December with NP101is, LFC, CEM-60, ASI2600mc-p. Temperature was 31 degrees. After one hour of 5 minute subs, we did the meridian flip and downloaded the images to check in the warming room. We were discouraged to see states as rounded triangles, which is characteristic of pinched optics.  The small triangles seemed to have common direction, like tilt, and definitely were not radial.

Actually, the overall two hours of data we collected processed OK, and BlurXTerminator did a good job of deconvolution, but all of the individual subs had the pinched defect.

We are trying to determine at what temperature this occurs through backyard experimentation. Any thoughts?

Kin
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