Rosse's Sketches of Spiral Nebulae

William Parsons, the third Earl of Rosse, used what was then the world's largest telescope to discover that some nebulae are spiral in shape. April 1845, Rosse discovered the spiral structure of Messier 51 (M51), the "Whirlpool Galaxy."

M51 - The Whirpool Galaxy (75 dpi). "Rosse's drawing of M51, the first occasion on which a spiral form was recognized in a nebula. The drawing was made in April 1845, and circulated at the June meeting of the British Association for the Advancement of Science."
M51 - The Whirpool Galaxy (150 dpi)
M99 (75 dpi). "Lord Rosse's sketch of M99 in Coma Berenices, a nebula whose spiral shape he recognized in March 1848...three years...since Rosse's recognition of" M51 (see images above).
M99 (150 dpi)

Copyrighted graphics and captions courtesy:

The Cambridge Illustrated History of Astronomy
Edited by Michael Hoskin
Cambridge University Press 1997
p. 254 - M51
p. 310 - M99

photoweb v1.2 - Phil Wherry