394 years ago, famous astronomer Johannes Kepler discovered the 3rd and also last of his planetary laws, and concluded the general revolution of our celestial world that started with Nikolaus Kopernikus about 100 years earlier. And that made him rather popular as he still is today. Did you know that there is a Kepler crater on the Moon, a Kepler crater on Mars, a Kepler asteroid, a Kepler supernova, of course there has to be a space mission named after him, even an opera
On January 9, 1848, Caroline Lucretia Herschel, German-British astronomer and sister of astronomer Sir William Herschel, passed away at age 98. She is best know for the discovery of several comets, in particular the periodic comet 35P/Herschel-Rigollet, which bears her name.
On January 7, 1610, physicist and astronomer Galileo Galilei turned his new telescope to the nocturnal sky to watch the planet Jupiter and discovered the eponymous four moons of Jupiter, Io, Europa, Ganimede, and Callisto.