As the third brightest object in our sky, spotting the ISS as it flies above our heads is a goal that can be firmly within our grasp. But what does it look like when the ISS, on a very rare occasion, crosses paths with our own Moon?

Astronomical photographer Gadi Eidelheit grabbed this incredibly brief shot of the ISS as it shot past the face of the moon. To get the shot, he explains on his blog, he had to calculate both distance and time very precisely. Having the Moon as a reference point, it's easy to get a much better sense of both the relatively small scale of the ISS and the speed with which it orbits us.

Check it out — and then use this tool to figure out how to see the ISS for yourself!