Not only are the whirling star trails against the static structure of the ISS absolutely stunning, but the vivid lines and colors of Earth's cities, weather and other phenomena are a uniquely gorgeous sight. As Pettit explains of his process:
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.You can see more of these incredible images right here. And for more insight into life on the International Space Station, you can follow Pettit on Twitter.