Hi Adam,
That's a great frame and (AFAIK) pretty much in line with what you can expect from the D550. All you need now, as many have already commented, is multiple frames to stack to mitigate the noise and you're laughing - nothing wrong with your processing skills I don't think!
http://www.iceinspace.com.au/forum/....s/thumbsup.gif
I attached my interpretation of the CR2, but honestly, it's probably not really that much of an improvement...
Best of luck!