On June 26, 1730, French astronomer Charles Messier was born. He is best known for his publication of an astronomical catalogue consisting of nebulae and star clusters that came to be known as the 110 "Messier objects". The purpose of the catalogue was to help astronomical observers, in particular comet hunters such as himself, distinguish between permanent and transient visually diffuse objects in the sky.
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.