A Messier marathon is an attempt, usually organized by

amateur astronomers Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers m ...

, to find as many

Messier object The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ''Catalogue des Nébuleuses et des Amas d'Étoiles'' (''Catalogue of Nebulae and Star Clusters''). Because Messier was only int ...

s as possible during one night. The Messier catalogue was compiled by French astronomer

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects''. Messier's purpose f ...

during the late 18th century and consists of 110 relatively bright

deep-sky object A deep-sky object (DSO) is any astronomical object that is not an individual star or Solar System object (such as Sun, Moon, planet, comet, etc.). The classification is used for the most part by amateur astronomers to denote visually observed fa ...

s (

galaxies A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

nebula A nebula ('cloud' or 'fog' in Latin; pl. nebulae, nebulæ or nebulas) is a distinct luminescent part of interstellar medium, which can consist of ionized, neutral or molecular hydrogen and also cosmic dust. Nebulae are often star-forming regio ...

e, and

star cluster Star clusters are large groups of stars. Two main types of star clusters can be distinguished: globular clusters are tight groups of ten thousand to millions of old stars which are gravitationally bound, while open clusters are more loosely clust ...

s).

When and where a marathon is possible

The number of Messier objects visible in any one night varies depending on a few factors, including the location of the observer, the duration of daylight and nighttime, and the season (the positions of the Messier objects relative to the Sun varies with the season).

Location

Because Messier compiled his catalog from a northern

latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...

, not all of the Messier objects are visible from the southern hemisphere. In particular, M81, M82, M52, and M103 make southern-hemisphere Messier marathons difficult, because they are all located at a declination of 60° north or greater. Although a Messier marathon can be attempted from any northern latitude, low northern latitudes are best. In particular, a latitude of around 25° north lends the best possibility to complete a Messier marathon at the right time of year.

Season

At low northern latitudes, particularly around latitude 25° north, it is possible to observe all Messier objects in one night during a window of a few weeks from mid-March to early April. In that period the dark nights around the time of the

new moon In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the naked eye, except when it is silhouetted against the Sun during a solar eclipse. ...

are best for a Messier marathon.

Other times of year

Less complete Messier marathons can be undertaken at other times of the year, with the actual percentage of Messier objects seen depending upon season and location. In particular, there is a short period around the autumnal equinox when most of the objects can be seen.

The marathon

The Messier Marathon was invented independently by American astronomers Tom Hoffelder,

Donald Machholz Donald Edward Machholz (October 7, 1952 – August 9, 2022) was an American amateur astronomer who was credited with the discovery of 12 comets that bear his name. Personal life and death In 2014, he married photojournalist Michele Machhol ...

, and Tom Reiland in the 1970s. Typically an observer attempting a Messier marathon begins observing at sundown and will observe through the night until sunrise in order to see all 110 objects. An observer starts with objects low in the western sky at sunset, hoping to view them before they dip out of view, then works eastward across the sky. 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. The evening can be 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 The Virgo Cluster is a large cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the lar ...

and the Milky Way's

Galactic Center The Galactic Center or Galactic Centre is the rotational center, the barycenter, of the Milky Way galaxy. Its central massive object is a supermassive black hole of about 4 million solar masses, which is called Sagittarius A*, a compact rad ...

) can prove to be challenging to an observer as well, and a Messier marathon will generally budget time for these regions accordingly.

Organized marathons

Marathons are typically organized by a local astronomy organization or

astronomical society A list of notable groups devoted to promoting astronomy research and education. Africa * African Astronomical Society South Africa *Astronomical Society of Southern Africa Asia China * Chinese Astronomical Society India * Akash Mitra Mandal *A ...

as a special type of

star party A star party is a gathering of amateur astronomers the purpose of observing objects and events in the sky. Local star parties may be one-night affairs, but larger events can last a week or longer and attract hundreds or even thousands of partici ...

. These are usually attempted at least once every year. Some clubs issue certificates/awards either for participation or for achieving a set number of objects.

References

External links

Messier Marathon History

Interactive Messier Catalog Greenhawk Observatory
SEDS *http://www.astras-stargate.com/holdm.htm
Peoria Astronomical Society's tips for participating in a Messier Marathon
Includes tips for preparations as well as for difficult portions of the marathon.
Clickable table of Messier objectsShort biography of Charles Messier and history of the Messier Object Catalog
SEDS *
Messier Objects Ranked By Observing Difficulty
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System *Marathon Amateur astronomy Observational astronomy