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Old 05-10-2015, 12:11 PM
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gregbradley is offline
Join Date: Feb 2006
Location: Sydney
Posts: 15,446
It must be the image scale is shifting. I think that is called focus breathing where the image scale shifts when you change focal length (lens shrinking as it gets colder).

Best to turn off temperature compensation and instead refocus a few times if needed although that may also do the same thing.

What sort of focus arrangement do you have?

For my own interest how well does the temp compensation work?

How did you do your flats? dusk flats, illuminated panel?

Were they bias subtracted when making the master flat or set as a master bias subtract when flat is applied?

How good are your darks?

Slightly off quality darks and biases can play havoc with some setups although I have only found lens imaging pretty forgiving.

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