DSO Astrophotography White Balance

[weixing]

Hi,
I currently use the flat field I took under normal sunlight to adjust my white balance, but not sure whether is it the correct method (the image turn very red on my mod camera... may be a bit too red) or is there any better method?

I think the proper way is to find a G2V star in the image to use it to calibrate the white balance, but finding a G2V star in the image is not easy leh... So I just wonder what method did you guys use?

Thanks and have a nice day.

[PETER LOO]

Hi Wei Xing, my 500D IR moded cam olso produced excessively red images, so i tried to used Auto white balance in the Nebulosity2 software, but image turn out excessively Blue now (see attached), not sure how to solve this, as i am relatively new in this field & still experimenting. n.b. i find that using the EOS native capture software would seems to produce images of greater dynamic range & truer colour than using MaximDL5 etc. not sure this is psycological.

[cataclysm]

Modified camera can be a real headache with white balance. What I normally do is start off by shooting with custom white balance. That will some what attenuate the the colour balance to be less red bias, but it will not entirely correct the problem. " Adjust Colour Background (offset)" in Nebulosity is a pretty good tool to correct the problem. It's design with ease of use in mind, particularly for DSLR user. I would normally pre-stretch the image and there after is a no-brainer one-click action. This function will work on most of the situation but not all the time, you can fine tune the image with the sliders to suit your taste. However as I had mentioned earlier, it's design with ease of use in mind, you cannot target the corrections, it's like gloss over the image with a broad brush stroke.

Recently I start to experiment with Pixinsight, and I must say it's a very versatile tool, and I am only scratching on the surface, and already I can see improvements with my images. The " Dynamic Background Extraction" function in Pixinsight can more precisely target the problem areas by sampling the background. " Colour Correction" function can further tweak the colour balance. Again it's a more interactive function by assigning reference points from your images to correct the colour in a more precise way. I am still geting acquainted with Pixinsight, delved deeper into it and I am sure there will be more useful features....

Just my 2 cents.