The United Kingdom is a terrible place to use a telescope, at least if you consider the weather. There might be one clear night a week, or worse. So it probably takes a certain amount of bravery for somebody like John McKeon to invest in a telescope and use it to look at the planets in between dodging clouds and rainstorms and snow.

Yet, McKeon—by all accounts an amateur telescope enthusiast—spotted something to spark the interest of a professional. A video on March 17, taken using only an 11-inch telescope, shows a flash of something impacting Jupiter. What’s more is he only thought to check the data after yet another amateur, Gerrit Kernbauer, posted a similar find on Facebook.

“I didn’t know for 10 days after I had recorded video that I had discovered it,” said McKeon, who originally took the footage to track the double shadow of moons Ganymede and Io moving across the planet. But after he saw the post, he immediately went through the 207 videos he took that night.