In camera multi-exposure consisting of 9 30 second exposures at f2.4. This is not just a long exposure, it is a multi exposure consisting of 9 frames.

Pentax K10D with 70mm f2.4 Limited. Auto EV compensation turned on.

Color corrected as best I could in photoshop.

I'm going to shoot some of these from some darker skies this winter. This was taken from my back yard with several street lights and house lights providing a lot of pollution. Correcting for sodium lights was a pain which threw off the star colors. But I like the results.