I've had a lot of fun doing Hydrogen line backyard astronomy. I wrote up an article on my experience [1]. These are two great sites as well [2][3].

[1]https://hmcguinn.com/posts/hydrogen-line/ [2]https://www.rtl-sdr.com/cheap-and-easy-hydrogen-line-radio-a... [3]https://physicsopenlab.org/2020/09/08/milky-way-structure-de...