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Old 19-07-2010, 09:35 AM
Dennis
Dazzled by the Cosmos.

Dennis is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 11,825
Quote:
Originally Posted by gbeal View Post
Dennis,
while no expert on this, I have had similar with some of my Ha shots.
I "think" or suspect it has something to do with the way I calibrate, or with the calibration frames.
Are these blemishes on the L, R, G, and B subs as well? Have you tried stacking with calibration? Just a though.
Gary
Hi Gary

Thanks for your reply. Yes – the “holes” appear to be in the same location in each LRGB sub frame as when I blink them, they don’t move at all.

Interestingly enough, I must have had a pretty accurate polar alignment as when each frame downloaded (via CCDSoft) on the PC, it registered perfectly with the previous frame as initially, I though that the camera wasn’t downloading, until I saw the filename change in the header.

This is looking more like a fixed pattern issue on the sensor I think?

Here is a quick assembly of the LRGB frames, a 1024x768 crop from the centre of the 1600x1200 fame.

Cheers

Dennis
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