I have had another go at processing the twelve 30-second (dark-subtracted jpeg) exposures that I took of the Milky Way setting over the Bristol Channel last September. I was not happy with the 8-bit look to the background subtraction and the lens-distortion. I used the beautifully complex free program hugin to correct for the barrel distortion of the lens and stack the images based on a spherical geometry. I had a long task, taking many hours to work out how to get the control points only on the stars. I eventually found a method for hugin to use to pick the control points, and it resulted in a beautifully stacked final image except it came out with a distorted perspective. So I stacked the shore images and recombined the image with the stars, and ran a background subtraction. The resulting processed image is much sharper but still with very slight trails from the individual 30 second exposures. I've reduced the scale to 0.25 here (jpeg), so the trails are barely visible. Altogether not bad for 12 minutes on a tripod perched on a windy clifftop.