div class=ts-pagebuttonPage 1button div class=ts-image amp-img class=ts-thumb alt=Page 1: An Easy Guide to Radio Astronomy src=https:reader035vdocumentssitereader035viewer2022080320575068141a28ab0f07ae82adhtml5thumbnails1jpg width=142 height=106 layout=responsive amp-img divp© 1960 Nature Publishing Grouppdiv