Strange artefacts in Swan Nebula image?

[Leebert]

Hi all,

The attached image of the Swan Nebula was probably my first successful guided image with reasonable subs. It was the result of 20 x 5 minute subs captured with an unmodified Nikon D5000 and Skywatcher 2" light pollution filter on a Vixen VC200L. It was only when I processed the image that I noticed that, when I zoomed in to the image I noticed a regular line pattern in the image running from approx 11 o'clock to 5 o'clock in the nebulosity in the image.

Any ideas as to what it might be? Just interested if anyone has seen it before?

Many thanks.

Cheers,

Lee

M17 Swan Nebula by MrLeebert, on Flickr

[laser_jock99]

Looks like trailed camera noise from the stacking. You might need take some dark frames next time.

[Leebert]

Interesting. Thanks - I hadn't thought of that.

It was taken at a friends last year and I don't recall taking darks as time was getting on and I had work the next day. I will try a reprocess with some darks that I took around the same time and see what comes out.

Cheers

Lee