Today’s Factismal: Astronomer Messier published his list of 45 objects that weren’t comets in 1777.
Let’s suppose that you have a huge room and that some busybody has scattered stuffed animals across the floor. Now suppose that you are trying to find your pet cat who has chosen to hide in the mess. How do you do it without leaving the sofa? If you are Charles Messier, you start by making a guide to where all of the stuffed animals are.
Messier was a comet hunter. By 1777, he had discovered eight new comets, which gave him a lot of fame and a position at the French Naval Observatory in Paris. But it is remarkably hard to discover a comet in the night sky; by the time it is clearly visible, some other astronomer has already seen it and claimed credit. So Messier spent a lot of time looking for something that was dim and diffuse and moved a little from night to night. But, like Congress, the sky is full of dim and diffuse objects. As a result, Messier kept “discovering” things that he’d already seen and knew weren’t comets. In order to keep his aggravation to a minimum, he started keeping a list of known non-comet fuzzy sky things. And to help the other astronomers, he published his list which is why we now call known non-comet fuzzy sky things “Messier objects”.
Today, the Messier catalog includes some 110 relatively bright and interesting things to see in the night sky. They range from globular clusters of stars to nebulae formed by exploding stars to places where stars are being born to entire galaxies of stars. Many local observatories have annual “Messier Marathons” where they attempt to see as many of the objects as they can in one night.
If you would like to look at the Messier objects, then the Star-Hopping Guide to the Messier Objects is your friend. And if you’d like to help classify new objects that have been discovered in the sky, then join the citizen science brigade at the Andromeda Project: