Astro Image Processing

So I have quite a few good shots of the moon and Orion nebula in RAW .NEF files but I need to do some serious image processing on them to improve image quality

Some obvious steps to do :

Stretching dynamic range

Noise removal - I did in-camera Long exposure noise reduction (NR) on D3 which tends to be considered inferior to PC based NR. Maybe more I can do on pc after stretching though

Gradient subtraction - should be able to remove sky glow and any vignetting by doing some Gaussian frames and subtracting them from images

Stacking - combine multiple shots to improve signal to noise ratio and level of detail.

Registax or ImagesPlus should be able to help with these tasks - Registax v5 is in the works so I'm trying the free v4 on the moon shots - not much of a noticeable improvement so far though. Waiting for my upgrade to ImagesPlus 3.5 to arrive in the post from the US.

Will update blog with progress reports.