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Bruce Murray Space Image Library

First sketch of the Whirlpool Galaxy's spiral structure

First sketch of the Whirlpool Galaxy's spiral structure
First sketch of the Whirlpool Galaxy's spiral structure This sketch of the Whirlpool Galaxy from 1845 represents a breakthrough in our understanding of the cosmos. Irish astronomer William Parsons had recently completed construction of the world’s largest telescope, the 72-inch "Leviathan of Parsonstown." He used this groundbreaking observatory to look at the Whirlpool Galaxy and saw, for the first time, the spiral structure of a galaxy. The Leviathan of Parsonstown remained the world’s largest telescope, in terms of aperture size, until 1917.