101 Must-See Cosmic Objects: M61

M61 was a problem for Charles Messier from the start. He first encountered the spiral galaxy May 5, 1779, when he mistook it for a nearby comet whose path he had been tracking. He repeated this error the following night and then again on the 11th before he finally noticed that the “comet” had not moved against the stars.

Once Messier realized his mistake, he noted the “nebula that happens to lie on [the comet’s] path and at the same point in the sky,” probably con