Launch the Color module.
See if StarTools comes up with a good colour balance all by itself. A good colour balance shows a good range of all star temperatures, from red, orange and yellow through to white and blue. HII areas will tend to look purplish/pink, while galaxy cores tend to look yellow and their outer rims tend to look bluer.
Green is an uncommon colour in outer space (though there are notable exceptions, such as areas that are strong in OIII such as the core of M42). If you see green dominance, you may want to reduce the green bias. If you think you have a good colour balance, but still see some dominant green in your image, you can remove the last bit of green using the 'Cap Green' function.
Thank you StarTools for turning my average photos into amazing ones.
Any other tools on the market today simply approximate the visual likeness of such star spikes and 'paint' them on.
You may have to configure your operating system to not scale up StarTools.
StarTools works on all 32-bit (NT-based) and 64-bit versions of Windows.
High-resolution data sets, such as those from a DSLR typically require at least 4Gb of RAM.
You can convert everything you see to a format you find convenient. Give it a try!