DSS problems

[MarkS]

Carole,

To me visually, both the "bias" and "no bias" images have exactly the same amount of banding.  I even verified this by subtracting one form the other and the banding completely disappeared - this shows there is the same amount in each one.  Did you post the right images?

There is also absolutely no problem with the colour balance in those TIFF files - here's a quick process I did by setting the black point and boosting the red by 20% and the blue by 10% (all done in IRIS as usual):



Larger version here: http://www.markshelley.co.uk/webdisk/carolepelican_iris.jpg

There's a odd blue patch of light top centre that might be caused by an external light source or internal reflections.  The colouring is good overall and it is possible to preserve good star colouring also.

The banding is typical of Canon and but I didn't try to remove it.

Mark

[JohnP]

Now that does look a lot better - nice one Mark. The link to the larger image is not the larger image by the way...?

[Carole]

Thanks for that Mark,

Did you post the right images?

Hmm, I think I had better check this out.

There's a odd blue patch of light top centre

Yes I wondered what that was.

I find it strange that the horizontal banding has only occured in 2 images that I have done and doesn't seem to appear in other images and until recently never had a problem with it at all.  

Which of the two images did you process Mark, I guess since there are very few dust bunnies that it was the one WITH the bias subtracted.

You have done an excellent job Mark thanks very much, I just need to try to make it work with DSS.  

Any further thoughts on the dust removal problem?

Thanks
Carole

[MarkS]

The link to the larger image is not the larger image by the way...?

Now fixed.

[MarkS]

Which of the two images did you process Mark, I guess since there are very few dust bunnies that it was the one WITH the bias subtracted.

I processed the bias subtracted one.

[Carole]

I'll have another go at processing the bias subtracted one then.

Thanks

Carole

[Mike]

There is really is no need for divided opinion.  If DSS is being used then follow the DSS instructions for creating/processing calibration frames.  If IRIS or PixInsight is being used then follow the relevant IRIS or PixInsight instructions.  If the instructions are ignored then expect to get it wrong!

i.e. RTFM !!