What is a Messier object and how do you observe it?

Messier objects are a set of 110 astronomical objects, including galaxies, nebulae, and star clusters, that were cataloged by French astronomer Charles Messier in the late 18th century. The purpose of the catalog was to help astronomers distinguish between permanent and transient objects, such as comets, which were often mistaken for new planets.

Messier objects can be observed using a telescope, preferably one with a large aperture, and under dark sky conditions. To observe Messier objects, you will need to locate them using a star chart or a smartphone app, and then point your telescope towards the object. Messier objects can be challenging to observe due to their low surface brightness, so it is important to use a technique called averted vision, which involves looking slightly to the side of the object rather than directly at it.

Observing Messier objects can be a rewarding experience for amateur astronomers, and many observing programs, such as the Messier Marathon, challenge observers to locate and observe all 110 objects in a single night.