If I ask you to image a radio telescope, you in all probability think about a big dish pointing to the sky, and even an array of dish antennas such because the Very Giant Array. What you doubtless don’t think about is one thing that resembles a TV dish in your neighbor’s yard. With fashionable electronics, it’s comparatively simple to construct your personal radio telescope. To know out how it may be finished, take a look at a current paper by Jack Phelps.
He outlines intimately how one can assemble a small radio telescope with a 1-meter satellite tv for pc dish, a Raspberry Pi, and another primary electronics equivalent to analog-to-digital converters. It’s a captivating learn, and one of the vital fascinating options is that his design is tuned to a frequency of 1420.405 MHz. That is the frequency emitted by impartial hydrogen. Because it has a wavelength of about 21 centimeters, the hydrogen emission line is typically referred to as the 21-cm line. Impartial hydrogen contains the majority of matter within the Universe. The 21-cm emission isn’t notably vivid, however as a result of there’s a lot hydrogen on the market, the sign is simple to detect. And wherever there’s matter, so too is the hydrogen line.
The emission is brought on by a spin flip of the hydrogen’s electron. It’s a hyperfine emission, which implies the road may be very sharp. In the event you see the road shifted a bit, that’s due to relative movement. Astronomers have used the road to map the distribution of matter within the Milky Manner, and have even used it to measure our galaxy’s rotation. Early observations of the road pointed to the existence of darkish matter in our galaxy. And now you are able to do it at house.
There are different radio objects you possibly can observe within the sky. The Solar is a well-liked goal given its sturdy radio sign. Jupiter is one other considerably vivid supply. It’s a cool pastime. Even if you happen to don’t intend to construct a radio telescope of you’re personal, it’s price trying out the paper simply to see how accessible radio astronomy has turn out to be.
Reference: J. Phelps. “Galactic Impartial Hydrogen Constructions Spectroscopy and Kinematics: Designing a Dwelling Radio Telescope for 21 cm Emission.” arXiv preprint arXiv:2411.00057 (2024).
