I was shooting between the clouds and buffeted by the wind last night.
37 x 8 second exposures at ISO 800, F3.5.
Stacked in DSS, I used PaintShopPro and a little bit of Photoshop to bring out the detail. Neatimage to smooth out some of the noise.
No tracking, just the camera on a fixed tripod.
I wonder what it would look like if there were 100 images stacked? If the clouds ever clear, I'll give it a go.
100 images would probably not look all that different from 37. At best you would reduce noise by about 40%. But I suspect you are really pushing the camera to its limits there (working not much above the so-called noise floor of the CCD) so actual improvement would be considerably less than that.
Nice shot jjj, I think you'll find that you could probably multiply the exposure time by at least 3 times (24 seconds), that will allow you to drop the ISO and lessen the noise. I have taken widefields (at the zenith) at 30 seconds with an 18mm F/L on the 20D with no appreciable star trailing.
