Currently on-board the International Space Station, NASA astronaut and Expedition 31 Flight Engineer Don Pettit, recently uploaded an incredible gallery of star trails to NASA’s Johnson Space Center Flickr page.
Speaking about the star trails that result from taking long exposure images (i.e., a photo taken with a slow shutter speed), Petit relayed some information about 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.”
In the amazing gallery below we get a surreal glimpse of Earth as seen from the ISS as it hurtles around our planet at an average speed of 17,500 mph (28,000 km/h). Enjoy!
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