Mars l18/11. Question aboutRGB balance

[5ash (Philip)]

Another mars through SW150ED .Not sure about RGB balance , it makes it bluer.
Regards philip

[Tulloch (Andrew)]

Hi Philip, what do you mean by "RGB balance makes it bluer"? Are you talking about Registax's Auto-RGB feature? If so, you should not use it for any planet that has a strong colour cast, like Mars, Uranus, Neptune or even Saturn. Why? Because it tries to produce a colour cast where all the channels are more-or-less equal. This is fine for Jupiter, bad for Saturn, and terrible for the others.

On the CN website, one accomplished planetary imager (DMach) uses an ASI290MC, and he chooses the parameters Wred=66 and Wblue=99 in FireCapture. This gives a good (but not perfect) white balance straight out of the camera. There may be a little correction to be done in post-processing, but nothing like what you are seeing.
https://www.cloudynights.com/topic/7...24/?p=10405666

You can see some of Darren's images here
https://www.astrobin.com/users/DMach/

Hope this helps,

Andrew

[5ash (Philip)]

Thanks Andrew , most instructions for processing in registax go through this step and I was concerned at the result. I will certainly try those white balance settings. Thanks again for pointing me in the right direction. Have reprocessed leaving out the auto balance step . The result is below.
Regards philip
PS is imPPG useful for planetary imaging or is it overkill?

[Tulloch (Andrew)]

Hi Philip, it certainly looks better, but not there yet.

I did a screen grab of your image, imported it into Photoshop and used the "Enhance/Adjust Colour/Remove Colour Cast" tool, selecting the polar ice cap as my white point. I also increased the black level a little to make the area around the planet black. This was the result. There's probably a similar tool in Gimp. This has done a pretty good job, the colours look about right, and you can see the dust storm as a slightly different orange colour on the LHS of the planet.

I've not used imPPG for planetary, my usual workflow is FireCapture/AS!3/Registax/Photoshop Elements, which works for me.

Andrew

[5ash (Philip)]

Thanks Andrew , I have a copy of photoshop 7 on an old xp computer and will see if I can do the same.
Regards philip

[5ash (Philip)]

Here’s my effort in gimp2 adjusting the the red channel in levels. This was a way suggested on the net to remove colour cast in gimp.
Regards philip

[Tulloch (Andrew)]

Looks much better Philip, well done