Here is what the page “On This Day in 1773: Charles Messier Spots the Whirlpool Galaxy, Decades Before Galaxies W” contains. On October 13, 1773, French astronomer Charles Messier added a faint, fuzzy object to his famous catalog—Messier 51, now known as the Whirlpool Galaxy. At the time, Messier was hunting comets and logging anything that might be confused with one. He had no idea he was documenting an entire galaxy beyond our own.
The Whirlpool Galaxy, located about 23 million light-years away in the constellation Canes Venatici, would later become one of the most studied galaxies in the sky. Its distinctive spiral structure, first sketched by Lord Rosse in 1845, helped astronomers realize that some nebulae were actually 'island universes'—separate galaxies far outside the Milky Way. Today, M51 is a favorite target for amateur and professional astronomers alike, and its interaction with a smaller companion galaxy provides a living laboratory for studying star formation and galactic evolution. For the complete material, the listing points back to the source inside the network.