Bad Astronomy

ISS transits the Moon!

German amateur astronomer Bernhard Christ was in the right place at the right time – due to very careful planning and foresight – and captured this astonishing scene:

[Click to embiggen.]

That’s the International Space Station crossing the face of the Moon, what astronomers call a transit (like an eclipse, but when something small goes in front of something big). This image is actually a composite of several images taken in a row, with some sharpening to make it cleaner looking.

The transit only lasted for 0.4 seconds, so Christ had to be on the ball to capture this. He used a digital astronomical camera that can take what is essentially video (really just rapid still shots, but after all that’s what video is), and processed the individual frames. It’s a gorgeous image, with the Moon looking really stunning.

And if you’re wondering why he only got four shots of the ISS, look again: there is a shot of it just inside the limb of the Moon, but it’s low contrast and hard to see. Just follow the path of the ISS as it crosses the Moon and you’ll find it.

My thanks to Herr Doktor Christ for allowing me to post this picture. Well done, and vielen Dank!