Astro Imaging star circles

[swphot]

I am having a problem with coloured fringing around stars which when processed in DeepSkyStacker appear as concentric rings.  I have checked and it is not a focussing problem as appears probably at first sight.  It appears more like chromatic aberration, but should not be with the equipment used (listed below).  I have enclosed two images, the first an unprocessed .fits image from CCDSoft (converted to .jpg for convenience) and the second a processed image in DeepSkyStacker.  Can anyone make any suggestions as to the cause.  The same problem occurs if I use no filters, or a IR/UV blocking and CLS filter.

Equipment: Takahashi TOA-130F and SBIG ST-2000XCM
Exposure: 2min binned 1x1


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[swashy]

Turn off the Hot Pixel detection in the 'register' dialogue box and 'stacking' dialogue box

worked for me when I had a similar problem, see my thread here

[swphot]

Brilliant - many thanks Swashy - it worked a treat!

[swashy]

Good to hear it 

[GJBC]

Ade you are a star,  I tried for ages with Ed to day to get this to stop.

There you go Ed  now put all that with what we went through to day and you will have a couple of super shots  oh yes and a headache from the steep learning curve. and then there is the back catalouge you are going to have to go through again to get rid of all those little donuts on all the other shots.

good to see you today

Grahame