not quite...

A nice clear night tonight and lots of stars out. Which lead me to try and get a decent shot of the stars. Which this isn't...

Okay, I understand that the earth is rotating, and so I'll get trails if I stack up the captured images. Fair enough. And I know that the 30s exposure leads to some blurring of the stars. In the absence of a telescope with a tracking mount this is how it's going to be.

Loads of mistakes: 30s is too long, saved images were JPEG (with lots of blocky artefacts), I didn't subtract the background yet, the gap between exposures is too long (30s exposure, 40s interval).

What I really need is a piece of software that will a) perform a high-pass filter, b) work out the rotational mapping between images and remap them all and c) stack the images correctly (not 8bpp, floating point please). There must be something out there already. Anyone?