When we think of astronomy, we usually think of telescopes made from lenses and mirrors that are used to focus the visible light emitted or reflected from distance objects. But this is far from the only option for astronomers. Almost any part of the electromagnetic spectrum can be used for astronomy. One part of the spectrum that’s particularly interesting are the radio and microwave frequencies. Thanks to a quirk of quantum mechanics, these frequencies allow astronomers to see where particular elements and molecules are clustered in the sky. However a radio telescope is very different from an ordinary visible light one. Since the wavelength of radio waves is very long, radio telescopes can’t form a picture all at once. Instead their function is more akin to looking at the world through a straw. Only by moving the straw around and recording the details of each “pixel” can you build up a full image. Building a simple radio telescope is actually fairly straightforward though and we build one that could “see” satellites in geosynchronous orbit, over 35,000 km away! Check out our build video to see it in action and how we built it: