Sometimes, it is desirable to keep an object or area from being included in an auto-generated mask. It is possible to have the auto-mask generator operate only on designated areas;
Final signal compositing is delayed until it is convenient and mathematically optimal.
Nevertheless the result can look quite pleasing when simply browsing past the image in a Facebook feed.
StarTools enables you to keep M42's colour constant throughout, even in its bright core.
StarTools comes with a unique colour balancing aid called MaxRGB.
You can convert everything you see to a format you find convenient. Give it a try!