Sadr (Gamma Cygni), NGC6910 on 5/6 September 2012

[The Thing]

Usual Kit, HEQ5, LX90 8" UHTC, Baader Alan Gee II Telecompressor, Astronomik CLS-CCD clip filter,Canon 1000Da, QHY5 on finderscope, PHD - no dithering (forgot to reset it after playing a bit), APT, CdC.

180 minutes in 5 minutes subs at iso800, processed in Deep Sky Stacker and Irfanview (I kid you not). Uncropped but is is an intersection stack so a little bit is missing off the edges. A little colour tweaking and basic sharpening. Dodgy stars are due to dodgy optics.

Bigger version here.

[MarkS]

Gamma Cygni being near the corner has definitely exaggerated the problem with the optics.

The nebulosity itself is looking good but you do seem to have some background gradients.  Probably not easy to remove.

Mark

[Carole]

Duncan, you mentioned at Mick's that DSS was not subtracting flats properly, and I wonder whether that is what has happened in this image as it looks a lot lighter in the middle. 

Dodgy stars are due to dodgy optics.

What's the problem with the optics?

I'd like to see this re-stacked using your other stacking programme Iris, and see if the gradients that Mark also talks about can be removed and that would make this a really nice image (stars aside). 

Carole