Star trails from space
Flight Engineer in the ISS, Don Pettit shot some really interesting photos using a long exposure technique. These shots are incredible and unique!
He explained the technique to achieve the image: “My star trail images are made by taking a time exposure of about 10 to 15 minutes. However, with modern digital cameras, 30 seconds is about the longest exposure possible, due to electronic detector noise effectively snowing out the image. To achieve the longer exposures I do what many amateur astronomers do. I take multiple 30-second exposures, then ‘stack’ them using imaging software, thus producing the longer exposure.”Source : NASA Flickr stream