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Old 19-10-2015, 10:35 PM
Tony_ (Tony)
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Join Date: Oct 2011
Location: Melbourne, Australia
Posts: 464
Help needed with flats

G'day,

I often get this problem with images using flats flats - uneven circles etc.
Imaging scope: sct 9.25" @ f 6.3.
Camera CDS 60s cooled. (ISO 800, -14c).

The flats are taken with a good quality light box at the same configuration and time as the lights. Same camera position etc. I used the same ISO and reduced the exposure so the histogram of the flats matches the lights. I used 20 flats. The image was stacked in DSS. I seem to get this problem mostly when I use the reducer. The reducer was used for the lights and the flats.

Does anyone have any ideas what is happening - thanks for any advice.

Regards,
Tony.
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