At some 25km across, the GMRT is one of the world’s largest radio telescopes
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Something happened at 7:21pm on the last day of February a few years ago. The thousands of boisterous kids who had roamed the Giant Metrewave Radio Telescope (GMRT) campus all day had all left. Left were some professional astronomers, some students, some weary staff and me, visiting for the day. We took a long walk past the GMRT’s antennae, then flopped down on the lawn for a chat. At precisely 7:21pm, a bright dot appeared in the north-west, scudded swiftly across the sky and vanished to the southeast. This was the International Space Station (ISS), making one of its regular passes overhead: for a few minutes, the brightest object in the sky. One astronomer mused as the dot vanished: “We become professional—then we forget about the amateur stuff! I’m so glad we saw the ISS!" On Science Day at the GMRT, the professionals are amateur again.