Very nice star trail Marc
If you are worried about the colour of the stars the key (I find) is to get the white balance of the sky correct in camera before you start taking the shots. Going through each RAW sub frame and adjusting the white balance is not my idea of fun when I can have up to 400 shots in a sequence. What this WB works out to be will depend on your skies and camera but for my Canon and very dark skies a White Balance Kelvin temperature of 3800 works well. Once you have that base you can then increase the saturation and vibrance of the colours in post processing to really make them pop. You can find a couple examples of my trails in this thread
http://www.iceinspace.com.au/forum/s...ad.php?t=82359
Can't wait to see more trails from you.
Cheers
Greg