Measure Distant Asteroids With a DIY Rig

What happened

That’s what happens when an asteroid orbits around the solar system and blocks the light of a distant star you’re viewing from Earth. When such a fortuitous alignment occurs, amateur astronomers can discern things about the asteroid that professionals can’t readily measure, even with their giant telescopes on high mountains .

With enough observers, they can collectively map that shadow, revealing the asteroid’s shape. Even folks on a limited budget can do this, because the size of an asteroid you can measure doesn’t scale with the size of your telescope.

If the occulted star is relatively bright, you don’t need much of a telescope at all. It relies on a GPS module [top] to provide a high-accuracy pulse once per second, is gated by an Arduino nano [middle] to prevent flashes occurring at the moment of occultation, and is then passed to a LED [bottom].