Correct White balance for 585MC to avoid green tinge output

In siril, it's super easy to do color calibration.

What I do is I select a small box somewhere on the image where there is no DSOs or stars and I color calibrate the whole image using that one spot, then I do a background extraction, and I get perfectly flat image; it works every time.



@Aaron  ages? ages to you too sir!

Well, I think you need flat calibration frames.

And about the magenta-ish star colors, I think that has to do with both, not having enough integration time, and not doing enough processing; it happens with me and I get stars that brownish or with no color, but I've never gone past one hour integration.

I suggest you decrease the brightness of the image to see more clearly the colors of your stars

Calibration subs should have no effect, unless DSS also does background neutralization alongside calibration (I think it does but calls it differently).

I was recommending flats to remove the donuts from his image (assuming they're removable), not fix any colors.

Aren't those donuts from sensor dust?

Use background extraction first!!! 
You don't need any calibration frame on IMX585 (it's a new type of sensor).

You "don't" need DARKS with the new sensors (although a still using them with mine QHY268 because of the hot pixels).

You defenly need flats flrames, no mether the sensor you use, especially if your sensor have dust spots, and not shooting in a very dark site.

It is much better to clean the sensor/lens than to use flats just for dust spots. It is a very long and tedious way to use the nights. And since dust can move around, doing 3minutes x 25 times flats each time can be really time consuming!

I would consider BIAS instead since the IMX585 has a high level of shot noise.

No, it's not, even if it this "cleaning" were practicable which isn't. Flats are taken either as dusk/down flats or using a flat panel and the time required in either cases is a tiny fraction of the actual exposures carried out through the session. Most importantly, flats needs taking to correct for PRNU as well as vignetting. Frankly, I'm not reallly even sure we are talking about the same thing here.

Bias signal shall not be confused and does not address "shot noise", which is intrinsic to actual process of capturing quantized data, such as photons. Bias correction only addresses the electronic bias error and relevant noise intinsic in powering the detector's electonics.

andrea tasselli:
No, it's not, even if it this "cleaning" were practicable which isn't. Flats are taken either as dusk/down flats or using a flat panel and the time required in either cases is a tiny fraction of the actual exposures carried out through the session.

Agreed wholeheartedly. Even if I spend plenty of time carefully cleaning my sensor, scope lens, etc, etc, there will still be dust on -something- by night's end, especially living in an urban environment. I take my flats immediately after shooting to compensate for anything that has built up on the lens throughout the imaging session, and it makes a substantial difference in image quality during stacking and stretching. 

You "don't" need DARKS with the new sensors (although a still using them with mine QHY268 because of the hot pixels).

You defenly need flats flrames, no mether the sensor you use, especially if your sensor have dust spots, and not shooting in a very dark site.

Also agreed, here. I find a noticeable difference using darks when shooting in Bortle 8+ conditions. If the sensor doesn't benefit majorly from darks in ideal light conditions, that'll be great in the future (moving to Bortle 4 skies in August).

Maybe I'm very fortunate, I have cleaned sensor 2 times, and NEVER cleaned refractor (maybe with a Newt there is lot different experience), and I leave my telescope out the whole night (minimum 9 hours). 

Dust on sensor with a closed refractor are nearly zero. (with a IMX585 I don't have to switch sensors).

But I don't live in a urban environment, in a bortle 4 sky near my house, and a 3 not so far away.

To be fair, the dust ends up on the scope lens, and not the sensor, since I'm shooting with refractors and SCTs. Might get a tiny bit of dust when I transfer from the Evostar 72ED to the C6, but I check for it before putting it on the scope. 

I almost always have some dust/dirt on the scope lens by night's end, depending on wind conditions. Definitely an advantage for you living away from the city!

Only for planetary/lunar, but yeah. Haven't noticed any issues with vignette or anything else.

Use background extraction first!!! 
You don't need any calibration frame on IMX585 (it's a new type of sensor).

You "don't" need DARKS with the new sensors (although a still using them with mine QHY268 because of the hot pixels).

You defenly need flats flrames, no mether the sensor you use, especially if your sensor have dust spots, and not shooting in a very dark site.

You don't need anything, doesn't mean it won't improve the result. 

In this photo about half the subs are with darks while the other half are with bias. There was no noticeable difference. But that was at 0 degrees with a f/6 instrument, and a rich background.

Only two days ago I was doing M97 at f/12. Was like "why is it so noisy" (despite the darks), then realisedI had forgotten to switch on the TEC so temperature was 12 degrees. So darks taken at 0 degrees would not correct adequately, and neither would a master bias. 

I too used to be of the opinion that you can do without calibration subs. There are cases that this is possible, but overall, I was wrong. Of course, they must be done correctly (which can be quite tricky, especially for flats). Otherwise, it is a very real possibility that they will harm the result. But when done correctly, they really do improve it. And it's not like you have to take them every time. In a closed system with controlled temperature, you can go months with the same master calibration subs. 

Cheers,
Dimitris

In Siril is subsky 1 to subtract the background

andrea tasselli:
In Siril is subsky 1 to subtract the background

Furthermore, select Color Calibration from the menu on the left (Image Processing) and click on Background Neutralization and you are done.

See also:

Colors — Siril 1.2.0 documentation

ALWAYS READ THE HELP FILES!