DSLR Calibration Issues - traveling noise & vignetting

[SteveBz]

Hi Guys,

I seem to be having ongoing calibration problems with my calibration whether I use DSS or Siril resulting in uncorrected vignetting and camera noise, which seems to be compounded by flexure in my guiding giving me traveling noise - if you look carefully the noise has a texture to it appearing from right to left and small 'worms' in it (there's one due South of the main subject, M106), which I guess correspond to hot pixels in the original data.

Here's the output using fits as an intermediary file and Siril to stack which gives a good idea of the problem (but I get the same issues with DSS and .tif).  This is about 3 hours from last night 5mins x 36 frames, 100 flats, 100 biases and 16 darks:

Here's an unstacked original:

Plus 100 stacked flats, converted to monochrome (in case that was the problem - it wasn't):

I feel I've tried everything, and I'm at a bit of loss as to what to do next.

Regards,

Steve.

Edited May 15, 2020 by SteveBz

[SteveBz]

Ok, there's a bit of weirdness here.  It seems that version 3.3.4 of DSS can't handle Nikon NEF files correctly - it describes them as 'gray' - at least on Linux.  For that reason I have been using ImageMagick or ufraw to convert to .tif files first for DSS and I used the same mechanism for convertying to .fits for Siril.  However, it appears that ufraw, imagemagick and rawtran (which I also used) all used dcraw under the hood (and DSS uses libraw - based on dcraw).  So all of my files have been having some conversion issues, maybe a bit of non-linearity when there should have been linearity, or brightening or something, which has caused the above effect.

When I started with .NEF files directly in Siril, demosaiced (debayered) in Siril, stacked my calibration files and then calibrated and stacked my lights in Siril and displayed in kstars, I get this:

Not a perfect image, but no vignetting and no walking noise.  Still need to do biases.

Amazingly, this has been going on since I started!!! Up until now I just cropped heavily and turned the brightness down.

I just need to work out how to turn it back into tiff without encountering any of these problems so I can edit in gimp (which uses RawTherapee under the hood), to edit.

Regards

Steve.

[michael8554]

Version 3.3.4 ? 

DSS has moved on a bit since then

Try DSS ver 4.2.3 

Supports D5000

My Canon .CR2 Raws have always been described as "Gray" in DSS ?

Michael

[wxsatuser]

17 hours ago, SteveBz said:

Ok, there's a bit of weirdness here.  It seems that version 3.3.4 of DSS can't handle Nikon NEF files correctly - it describes them as 'gray' - at least on Linux.  For that reason I have been using

This issue keeps arising with the likes of DSS and other stackers.
All RAW files are gray scale it's the colour filter array that turns them into colour.

Do not worry about the fact they are reported as gray.

Also RAW files will lack contrast, colour and brightness, again do not worry about this.
Astro images will lack all of these especially and it's up to you, the processor, to bring them out.

Edited May 16, 2020 by wxsatuser

[SteveBz]

8 hours ago, wxsatuser said:

All RAW files are gray scale it's the colour filter array that turns them into colour.

Do not worry about the fact they are reported as gray.

Ok, great I understand.  Thanks for that.  I'm running a session now.

What about master calibration files?  If I put in 100 flats, for instance, in .NEF form, it creates a MasterFlat, what format should I store this in, so I can use it again (tif or fit).  The issue for me was, if I store it in tif, then it comes back as being RGB and incompatible with the monochrome raw files?

Regards

Steve.

 

[michael8554]

My Canon Master Flat is saved as a TIF and happily reloads along with the Raw Picture files, showing as a TIF in the list.

But that's in 4.2.4, ver 3.3.4 may be different.

Michael

[SteveBz]

13 hours ago, michael8554 said:

My Canon Master Flat is saved as a TIF and happily reloads along with the Raw Picture files, showing as a TIF in the list.

But that's in 4.2.4, ver 3.3.4 may be different.

Michael

OK, thanks, I'll try it.

Although I have to say, I've just reinstalled Siril.v.99 and it's amazing. I'm no longer so drawn to DSS.

Regards

Steve.