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Stacking Artefacts-Please Help
Stacking Artefacts-Please Help
Hi Guys,
after a relatively long absence from AP I used one of the best nights possible to get back into it.
The RAW´s I got from my DSLR are beautiful and low noise. I took almost 30 images and stacked about 20 including darks, flats, dark flats, offsets.
The staking went without error, I followed DSS´s recommended settings but changed from Median Combination to Average.
The result is disconcerting: the stacked image looks like someone racked through it. Or as if strong winds are blowing through the (Lagoon) nebula.
I have attached a single exposure as well as the stacked image. Both have been significantly reduced in size/quality for web posting purposes. But it is imediately evident that the single exposure is much smoother and shows none of the artefacts that (I guess) were intoduced through stacking.
The "racking"-issue is not unknown to me and is more or less present in all my stacked images. So far, however, the stacking gain outweighed it. I this case I might as well not stack at all and be happy with what I got out of the box. I would like to be better with this. Does somebody here know what the culprit might be?
I would really appreciate if somebody could point me in the right direction.
Details below:
Camera: Canon 450D
Filter: Astronomik CLS
Scope: Celestron OmniXLT150 (150mm Newton)
Exposure Time: 210s
Number of Exposures in stack: 21
Percentage of Exposures stacked: 80%
Many Thanks.
Max
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