Ralf Vandebergh likes to take pictures of what he can spot with his 10-inch telescope, and has sighted the International Space Station as it drifted over Europe several times. Back in March, however, he was treated to something new: a spacewalk.

Vandebergh compared his pictures to live recordings from NASA and was able to confirm that astronauts were indeed working on the earth-side of the ISS to deploy the UCCAS, or unpressurized cargo carrier attachment system. He details his finds in the gallery below.

Ralf Vandebergh, via Wired