M33 with dslr

[russp]

M33 with a Nikon D500 on a 127mm frac. 20 5min dithered subs with superbias only - processing in PixInsight. Any advice or comments welcome - I'm still getting to grips with processing. Full 74Mp image on flickr

 

[Thalestris24]

Hi

I think that's pretty good! However, M33 has low surface brightness so you need lots and lots of data to do it justice.

Louise

 

[MikeODay]

Nice image with lots of detail in the arms of the galaxy and very good round stars that retain their colours.  

The overall colour balance is unusual - how did you go about balancing the image?

 

[russp]

18 minutes ago, MikeODay said:

Nice image with lots of detail in the arms of the galaxy and very good round stars that retain their colours.  

The overall colour balance is unusual - how did you go about balancing the image?

 

I'm not sure I did! I should maybe look at some other images and revisit that! The RGB histograms weren't aligned well in the curves adjustment but aligning them made it look green and wierd so I just left it and carried on !

 

[MikeODay]

Mmm, when you say you just left it, do you mean that the DSLR format conversion settings in Pixinsight were set to auto white balance?

[russp]

5 minutes ago, MikeODay said:

Mmm, when you say you just left it, do you mean that the DSLR format conversion settings in Pixinsight were set to auto white balance?

No - I'm using pure RAW files and then debayering after calibration - so no white balance involved in format conversion. 

 

[MikeODay]

6 minutes ago, russp said:

No - I'm using pure RAW files and then debayering after calibration - so no white balance involved in format conversion. 

 

Unusual then.  In my case the image would be very green.  

Like you I process with raw files and then I perform a “daylight” colour balance by scaling the RGB channels using the camera’s “direct sun” channel ratios.  I follow this up with DynamicBackgroundExtraction to remove/reduce the light pollution and finally tweak the colour a little in Photoshop using the colour balance sliders.

I have also been playing around with the PhotometricColorCalibration tool with good results on some ( but not all ) images.

[alacant]

Hi. Nice shot. I think it could be improved a lot by adding flat frames to the mix. HTH and clear skies.

[russp]

12 hours ago, alacant said:

Hi. Nice shot. I think it could be improved a lot by adding flat frames to the mix. HTH and clear skies.

Just out of interest what do you see that you think flat frames would improve ? - thanks

 

[wxsatuser]

2 hours ago, russp said:

Just out of interest what do you see that you think flat frames would improve ? - thanks

 

The vignetting for one.

If you have PI, DBE can sort some of it, try Division for vignetting and Subtraction for gradients.
Obviously flats would be a good idea if you can do some.

[alacant]

4 hours ago, wxsatuser said:

vignetting for one

They will fix the dust blotches too. HTH.