This is a composite of a series of images photographed from a mounted camera on the Earth-orbiting International Space Station, from approximately 240 miles above Earth. Expedition 31 Flight Engineer Don Pettit said of the photographic techniques used to achieve the images: "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." A total of 18 images photographed by the astronaut-monitored stationary camera were combined to create this composite. Taken on May 17, 2012.