I knew it could be a subject to open, don't found clear response about what to tune.
So, going on about color balance : it appears that the day tuning is innapropriate vs night astronomic shooting.
I used the previous recorded color balance to shoot again M42 with an IR-cut-filter.
You can see over-compensed color balance (original stacked file from Sharpcap) here
(dark is purple..., histogram clearly unbalanced)
![](</s><URL rel="ugc nofollow" url="http://atom.lylver.org/AstroSurf/ZWO%20ASI%20185MC/day-night-balance.jpg"><LINK_TEXT text="http://atom.lylver.org/AstroSurf/ZWO%20 ... alance.jpg">http://atom.lylver.org/AstroSurf/ZWO%20ASI%20185MC/day-night-balance.jpg</LINK_TEXT></URL><e>)
So IMO could be :
a) daylight balance is over our yellow sun : so blue is over compensated, perhaps red too
b) human night vision goes to more sensitivity to blue at night. (550nm day pic, 500nm night. It is well documented in medecine articles
As image post-processing could give odd results, what should be done ?
Let the standard gain tuning before shooting and do some special action or pre-process when imaging is done (before stacking) ?
