A Messier marathon is an attempt, usually organized by amateur astronomers, to find as many Messier objects as possible during one night. The Messier catalogue was compiled by French astronomer Charles Messier during the late 18th century and consists of 110 relatively bright deep-sky objects (galaxies, nebulae, and star clusters).
Here are some great Wikipedia links for background:
- https://en.wikipedia.org/wiki/Messier_marathon
- https://en.wikipedia.org/wiki/Messier_object
- https://en.wikipedia.org/wiki/Charles_Messier
Here are some great Messier Marathon Links from SEDS: