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.
J. Scheer, K. Bruning, T. Frohlich, P. Wurz, и W. Heiland. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 157 (1-4):
208--213(августа 1999)