Building a Window into the Galaxy: Designing a Home Radio Telescope for Detecting 21 cm Hydrogen Emission

Phelps’ study outlines the design of a low-cost, home-built radio telescope capable of detecting the 21 cm hydrogen line, allowing for the observation of neutral hydrogen distribution and motion within the Milky Way. By measuring Doppler shifts, the setup captures velocity data for hydrogen clouds, revealing details about the galaxy's structure and rotational dynamics. Through effective signal processing and interference reduction, this project makes advanced galactic observations accessible to amateur astronomers, helping map the motion of hydrogen gas in the Milky Way's spiral arms.