Messier Discovers Whirlpool Galaxy (1773)

Charles Messier, a French astronomer, discovered the Whirlpool Galaxy on October 13, 1773. This interacting grand-design spiral galaxy, located in Canes Venatici, was designated M51 in his catalogue to help observers distinguish permanent from transient diffuse objects.

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Background and detail

Background. Charles Messier was a French astronomer who published an astronomical catalogue of 110 nebulae and star clusters. His purpose was to help observers distinguish between permanent and transient visually diffuse objects. The first version of this catalogue, containing 45 objects, was published in 1774 in the journal of the French Academy of Sciences in Paris.

Discovery. The Whirlpool Galaxy, also known as Messier 51a or NGC 5194, is an interacting grand-design spiral galaxy in the constellation Canes Venatici. It was the first galaxy classified as a spiral. Messier discovered it on October 13, 1773, while hunting for objects that could confuse comet hunters, designating it as M51.

Catalogue. Messier's catalogue came to be known as the Messier objects, referred to with the letter M and their number. The Whirlpool Galaxy was designated as M51 in this catalogue. The first version of the catalogue containing 45 objects was published in 1774 in the journal of the French Academy of Sciences in Paris.

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