Plan and Prepare for a Messier Marathon

Locate, observe, and log all 110 Messier Objects in one night.

The 18th-century French astronomer Charles Messier (pronounced MEZZ-ee-yay) lived for finding comets. Every clear night, he was out with his telescopes, trying to be the first to identify each new comet. But Messier had a problem. It’s very difficult to tell the difference between a dim comet and many other dim astronomical objects. The only way he could know for sure that he’d found a new comet was to observe the object over several nights. Over that period, a comet moves relative to the background stars, while other objects remain fixed in position.

On the night of 28 August 1758, Messier was looking for comet Halley on its first predicted return when he happened across a dim object in the constellation Taurus that looked very much like a comet. He studied that object intently over the next several nights, only to find that it didn’t move against the background stars. Disgusted at the waste of time, Messier decided to create a list of these obnoxious fixed objects that masqueraded as comets so that he and other observers could avoid wasting time looking at them in the future. He carefully logged the position of the object, and recorded it as Messier Object 1, or M1. (That object, now known as the Crab Nebula, is one of the most famous astronomical objects.)

Over the years, Messier added to his list of objects until it eventually included 103 objects, one of which was a duplicate. ...

Get Astronomy Hacks now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.