Astronomers want to build giant telescopes on the moon. They're already drafting blueprints and making proposals, some with cash from NASA.

Of course, you could build your own, although to get up to 500 meters might be a stretch. If your backyard isn’t that big, you can build a tiny radio telescope too.

Foil-lined foam insulation board, scraps of lumber, and a paint-thinner can hardly sound like the tools of a radio astronomer. But when coupled with an SDR, a couple of amplifiers, and a fair ...