A very popular, comprehensive tutorial titled "Processing a (noisy) DSLR image stack with StarTools" by Astro Blog Delta.
Chances are that the image looks terrible, which is - believe it or not - the point.
The two aspects - colour and luminance - of your image are neatly separated thanks to StarTools' signal evolution Tracking engine.
The Color module is very powerful - offering capabilities surpassing most other software - yet it is simple to use.
Please note that other parameters such as the 'Threshold', 'Max feature size', 'Filter sensitivity' and 'Exclude color' have no effect in this mode.
You can convert everything you see to a format you find convenient. Give it a try!