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Old 14-01-2009, 07:26 PM
TrevorW
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Doughnuts

I'm stacking only a few 180s frames in DSS with darks and flats applied yet the dimmer stars appear as doughnuts. Yet in each frame prior to stacking they do not.

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Old 14-01-2009, 07:53 PM
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iceman (Mike)
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Can you post a selection of before and after's, reduced in size and posted as jpeg?
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Old 14-01-2009, 09:28 PM
TrevorW
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Mike I stacked the images in PS CS3 and the doughnuts did not appear.

Attached are a DSS stack plus one of the unstacked frames

Cheers
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Click for full-size image (ngc2477 9m 3 frames darks flats DSS.jpg)
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Click for full-size image (ngc2477 180s_002.jpg)
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Old 14-01-2009, 09:46 PM
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Octane (Humayun)
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Trevor,

Looks like some kind of weird pre-processing artifact?

Regards,
Humayun
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Old 14-01-2009, 10:14 PM
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Have a look at the hot pixel removal.
It is probably too agressive, removing the centre of the stars. I would turn it off completely, and then if you're not happy, put it back on and start with very small numbers and work your way up.
It's on the "cosmetic" tab of the stacking parameters.

Turbo
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Old 14-01-2009, 11:56 PM
Zuts
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Doughnuts, Yummmmmm
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Old 15-01-2009, 09:54 AM
TrevorW
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Quote:
Originally Posted by turbo_pascale View Post
Have a look at the hot pixel removal.
It is probably too agressive, removing the centre of the stars. I would turn it off completely, and then if you're not happy, put it back on and start with very small numbers and work your way up.
It's on the "cosmetic" tab of the stacking parameters.

Turbo
Dropped the pixel size and strength and appears to have fixed the problem

Thanks
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Old 15-01-2009, 10:39 AM
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turbo_pascale (Rob)
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Excellent..... It might be worth posting the same image up as a comparison for others to see the difference.....

Turbo
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