NASA astronaut, Don Pettit took these stunning long exposure photographs from the orbit of the ISS during Expedition 31. The images were created by combining 18 separate long-exposure photographs of star trails and city trails from the International Space Station.
Pettit explains: “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.”
They are beautiful.