What do star trails look like from the ISS?

A view that no one ever had — not even from space — until Astronaut Don Pettit changed everything with these stunning photographs.

“This job is a great scientific adventure. But it’s also a great human adventure. Mankind has made giant steps forward. However, what we know is really very, very little compared to what we still have to know.” –Fabiola Gianotti

To photograph star trails from Earth, simply point your camera and let the Earth rotate, leaving the shutter open.

*Image credit: Chris Luckhardt / @chrisluckhardt on Twitter, of a long-exposure photograph of the stars from Earth.*

But our 24 hour period is nothing compared to the ISS astronauts, who circle the entire Earth every 90 minutes at some 17,000 mph (27,000 kph).

*Image credit: NASA, of ISS expedition 28 in 2011, of the ISS cupola over Australia at night.*

In February of 2010, the cupola was delivered and installed, giving astronauts a new view of the Earth. It also gave them the opportunity to experiment with photography.

*Image credit: NASA / Astronaut Don Pettit / @astro_pettit on Twitter, of star trails from inside the ISS cupola.*

The first astronaut to take true advantage of this was Don Pettit, who stacked short-exposure photos together to produce the stunning effects of star trails.

*Image credit: NASA / Astronaut Don Pettit / @astro_pettit on Twitter, of star trails seen through the machinery of the ISS, with the Earth visible at the bottom of the frame.*

My star trail images are made by taking a time exposure of about 10 to 15 minutes. […] 30 seconds is about the longest exposure possible, due to electronic detector noise effectively snowing out the image.

Image credit: NASA / Astronaut Don Pettit / @astro_pettit on Twitter, of star trails as the ISS flies laterally over the Earth. The stars appear in the Earth’s foreground due to the faint, transparent nature of Earth’s atmosphere.

I take multiple 30-second exposures [an amateur astronomer technique], then ‘stack’ them using imaging software, thus producing the longer exposure.

Image credit: NASA / Astronaut Don Pettit / @astro_pettit on Twitter, where the stationary “point” is due to the ISS’ rotation to keep the Earth beneath it, and not to any celestial or terrestrial motion.

The stationary points are neither the north nor south poles, but rather arbitrary points about the ISS’s axis of rotation.

Image credit: NASA / Astronaut Don Pettit / @astro_pettit on Twitter, of the red (hydrogen) airglow above the green (oxygen) airglow, with yellow city lights and blue lightning strikes on Earth. Star trails glitter above.

The green and red airglows, yellow city lights and even lightning (in blue) are all visible from this unique vantage point.

https://www.youtube.com/watch?v=TOQrx-7qgak

Mostly Mute Monday tells the story of a single astronomical phenomenon or object in pictures and other visuals, with no more than 200 words of text.

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