The effect of light pollution filters on native one-shot color camera white balance

[mAnKiNd]

Hello,

Rather than pasting a large document here and taking up lots of space, I've instead written a report you can access by downloading it here:

https://docs.google.com/document/d/127e ... sp=sharing

I have enabled the can comment function in the document, so please feel free to leave your comments in the actual writeup if you wish to provide any edits or spot any errors in need of corrections. Or leave them here

I hope this helps, it was a test I did for my own "finding out", which turned into me writing it up to share with you.

All the best,
Minos

[AndyBooth]

Very interesting indeed.
Thanks.

[turfpit]

A sturdy piece of work Minos. Good to see a systematic investigation and detailed write-up. It will take a couple of reads for me to digest thoroughly.

Dave

[mAnKiNd]

Thanks,

I suppose the quick take home message is this graph, which shows how each LP filter affects the %RGB signal intensities for my OSC camera. 0% difference in all three RGB signal intensities would achieve a "theoretically unison" white balance.

It shows how green is still the most intense signal except from the UHC+UV/IR combo, which had an orangey cast (see figure 15 in the write-up above).

None of these LP filters achieved a particularly unison native white balance in this specific test, but some interesting results arose.

Screenshot_20200205-133727.png (390.14 KiB) Viewed 2702 times

Cheers
Minos

[mAnKiNd]

Thought I'd post the raw screen grabs from all the filters I tested (some are totally non sensical!) for quick reference.

The only filter that achieved native OSC white balance is the ZWO 850nm

Sorry for all the subsequent posts, I could only fit three pics in each post.

I hope to add more test results in the future.

no filter.png (764.71 KiB) Viewed 2626 times

Optolong_Clear_Focusing.png (763.88 KiB) Viewed 2626 times

Astronomik_UV_IR_L-3.png (768.21 KiB) Viewed 2626 times

[mAnKiNd]

Optolong_Moon___Skyglow.png (769.01 KiB) Viewed 2626 times

Astronomik_CLS.png (760.13 KiB) Viewed 2626 times

Astronomik_CLS_+_Astronomik_UV_IR_L-3.png (769.66 KiB) Viewed 2626 times

[mAnKiNd]

Astronomik_CLS_CCD.png (891.85 KiB) Viewed 2620 times

Astronomik_UHC-E.png (764.41 KiB) Viewed 2626 times

Astronomik_UHC-E_+_Astronomik_UV_IR_L-3.png (767.03 KiB) Viewed 2626 times

[mAnKiNd]

Astronomik_UHC.png (660.32 KiB) Viewed 2626 times

Astronomik_UHC+_Astronomik_UV_IR_L-3.png (664.68 KiB) Viewed 2626 times

ZWO_850nm_IR.png (663.51 KiB) Viewed 2626 times

[mAnKiNd]

Astronomik_Deep_Sky_R.png (558.8 KiB) Viewed 2625 times

Astronomik_Deep_Sky_G.png (642.22 KiB) Viewed 2625 times

Astronomik_Deep_Sky_B.png (634.94 KiB) Viewed 2625 times

[mAnKiNd]

Astronomik_H-beta_12nm_CCD.png (748.81 KiB) Viewed 2533 times

Optolong_H-beta_25nm.png (662.74 KiB) Viewed 2625 times

Optolong_Oiii_25nm.png (655.57 KiB) Viewed 2625 times