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 Large Array. What you possible 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 performed, try a latest 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 reminiscent of analog-to-digital converters. It’s a captivating learn, and one of the 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 usually known as the 21-cm line. Impartial hydrogen includes the majority of matter within the Universe. The 21-cm emission isn’t significantly vivid, however as a result of there may be a lot hydrogen on the market, the sign is simple to detect. And wherever there may be matter, so too is the hydrogen line.
The emission is caused by a spin flip of the hydrogen’s electron. It’s a hyperfine emission, which implies the road could be very sharp. In the event you see the road shifted a bit, you already know that’s due to relative movement. Astronomers have used the road to map the distribution of matter within the Milky Means, 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 residence.
There are different radio objects you possibly can observe within the sky. The Solar is a well-liked goal given its robust radio sign. Jupiter is one other considerably vivid supply. It’s a cool pastime. Even should you don’t intend to construct a radio telescope of you’re personal, it’s price testing the paper simply to see how accessible radio astronomy has change into.
Reference: J. Phelps. “Galactic Neutral Hydrogen Structures Spectroscopy and Kinematics: Designing a Home Radio Telescope for 21 cm Emission.” arXiv preprint arXiv:2411.00057 (2024).
