Messier marathon

Lore & Background

The Messier Marathon was invented independently by American astronomers Tom Hoffelder, Donald Machholz, and Tom Reiland in the 1970s. Typically an observer attempting a marathon begins at sundown and observes through the night until sunrise, starting with objects low in the western sky at sunset and working eastward. By sunrise, the successful observer will be observing the last few objects low on the eastern horizon, hoping to see them before the sky becomes too bright due to the rising sun.

Reader's Guide

The Messier marathon is notable as a test of stamina and willpower, depending on weather conditions and the physical fitness of the observer. Particularly crowded regions of the sky, namely the Virgo Cluster and the Milky Way's Galactic Center, can prove challenging, and a marathon will generally budget time for these regions accordingly. Marathons are typically organized by a local astronomy organization or astronomical society as a special type of star party, usually attempted at least once every year. Some clubs issue certificates or awards either for participation or for achieving a set number of objects. The marathon's significance lies in its ability to engage amateur astronomers in a systematic, night-long observation of Charles Messier's catalog, with the best chance of seeing all 110 objects occurring at low northern latitudes around 25° north during a window from mid-March to early April, especially on dark nights near the new moon.

Did You Know?

• The Messier marathon was invented independently by three American astronomers in the 1970s.
• A latitude of around 25° north offers the best possibility to complete a marathon at the right time of year.
• The optimal season for a full marathon is a few weeks from mid-March to early April.
• Some clubs issue certificates or awards for participation or achieving a set number of objects.

Born from a Comet Hunter's Frustration

The Messier catalogue was born not from a grand ambition to map the cosmos, but from sheer irritation. Charles Messier, a French astronomer of the eighteenth century, was consumed by the search for comets. Yet every faint smudge he spotted demanded hours of verification to rule out a fixed nebula, cluster, or galaxy. To spare himself this recurring ordeal, he began assembling a list of non-comet objects that kept derailing his observations. Working alongside his assistant Pierre Méchain, Messier compiled what would become one of the most celebrated inventories in all of astronomy. A preliminary edition appeared in 1774 with forty-five unnumbered entries, the list grew to seventy by 1780, and the final version of one hundred and three objects was published in 1781. What started as a personal nuisance list has endured for over two centuries as the definitive reference for deep-sky observation, with its entries still universally cited by their M-numbers to this day.

The Marathon: One Night, One Hundred and Ten Targets

In early spring, a distinctive astronomical tradition draws observers of every experience level together for what is popularly called a Messier marathon. The ambition is considerable: to visually locate all one hundred and ten Messier objects within a single night. This is feasible because the catalogue was assembled from the vantage point of Paris, spanning the sky from the north celestial pole down to roughly thirty-five point seven degrees south celestial latitude, so the targets rise and set in a sequence that tracks the progress of the night. What makes the marathon especially welcoming is that these targets were originally identified with a modest refracting telescope of about one hundred millimeters aperture. They rank among the brightest and most visually striking deep-sky objects in their respective categories, so modern observers with larger instruments can resolve remarkable fine detail. The event underscores that some of the universe's most spectacular structures remain accessible to the human eye, linking present-day stargazers to an eighteenth-century French comet hunter's daily frustrations.

A List That Grew After Its Author

Messier's final published catalogue in 1781 listed one hundred and three objects, yet the story did not end there. For decades the total was commonly cited as one hundred and two, owing to what was long regarded as an erroneous inclusion of Messier 102. Méchain had observed an object and relayed his notes to Messier, but later concluded it was simply a re-observation of M101, though some sources identify the target as the galaxy NGC 5866. The genuine expansion of the list came from later astronomers who uncovered side notes in Messier's and Méchain's manuscripts. In 1921, Nicolas Camille Flammarion added M104 after spotting a note in Messier's personal copy of the 1781 edition. Helen Sawyer Hogg contributed M105 through M107 in 1947, Owen Gingerich added M108 and M109 in 1960, and Kenneth Glyn Jones included M110 in 1967. These additions, drawn from marginalia and unpublished observations, brought the total to one hundred and ten, demonstrating how a single astronomer's working notes could reshape a catalogue for generations of observers.

Scientific Depth Meets Backyard Accessibility

The Messier catalogue is remarkable not only for its size but for the breadth of celestial phenomena it encompasses. Among its one hundred and ten entries are diffuse nebulae, planetary nebulae, open star clusters, globular clusters, and galaxies, essentially the full spectrum of what astronomers call deep-sky objects. Messier 1, the Crab Nebula, is the remnant of a supernova explosion, while M31 is the great Andromeda Galaxy, a spiral system. Crucially, nearly all Messier objects are among the closest members of their respective classes to Earth. This proximity means they have been intensively studied with professional-grade instruments capable of resolving fine structural details invisible to the unaided eye, and the Concise Catalog of Deep-sky Objects compiles astrophysical summaries for each entry. Yet despite their scientific depth, these objects remain fundamentally visual targets, bright enough to be seen with modest glass, making them the enduring bridge between professional astrophysics and the backyard telescope.