Only now garnering online attention, the collection of photos were taken by Expedition 31 flight engineer Don Pettit and originally posted by NASA back in 2012. A two-time visitor to the International Space Station and the first astronaut to successfully enter a commercially-built craft docked with the ISS, Pettit first came to prominence over a decade ago via his ‘Saturday Morning Science’ experiments aboard the station, gaining further fame on his second mission through videos utilising Rovio’s Angry Birds to help explain low-gravity physics.
One of the most prolific astronaut photographers, Pettit was also responsible for building a Haig tracking mount aboard the ISS (from spare parts), to facilitate the capture of sharper high-res images of the Earth from the station.
For his star trails project, Pettit’s aim was to ape the long-exposure photography techniques of old, albeit with ultra-high resolution digital equipment. This presented a key technical challenge: “With modern digital cameras, 30 seconds is about the longest exposure possible, due to electronic detector noise effectively snowing out the image,” says Pettit. “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.”
36 of Pettit’s beautiful long-exposure images, shot at a resolution of 4256 x 2832 pixels, can be viewed and downloaded via NASA’s own flickr account.
And for more about Pettit’s space photography, check out this video on YouTube.