The complete list of 110 Messier objects is called the Messier Catalog. And they are classified into three broad categories as one nebulaestar clusters or galaxies.
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What are Messier objects?
Messier’s list begins with 103 deep-sky objects observed by the 18th-century French astronomer Charles Messier. Seven more objects added in the 20th century bring the list up to 110 objects. Specifically, these deep-sky objects refer to astronomical bodies other than stars or planets. All Messier objects look like blurry, hazy spots in the sky.
The names of Messier objects come from their number in Charles Messier’s original catalog. For example, the Pleiades star cluster has the number 45, Messier 45 or simply M45. In addition to numbers, many Messier objects have common names, such as the Pleiades aka the 7 Sisters.
A small telescope can easily observe Messier objects. And some of them are visible only with binoculars or even with the naked eye.
Because all Messier objects are relatively bright, finding Messier objects is an ideal project for the beginning stargazer.
Messier Marathon: View all Messier objects
In addition, every year in March, all 110 Messier objects are visible in a single night. Astrologers all over the world take advantage of this coincidence and plan the so-called Messier’s Marathon. Basically, participants use binoculars or binoculars and try to see as many Messier objects as possible during 12 continuous hours of darkness. In order to see them all, sightings must begin at sunset and end at sunrise the following morning. Anyone observing 100 or more objects is satisfied with their results.
Note, however, that several Messier objects are difficult to capture because they are only visible very close to the horizon. For best results, use a List of Messier Marathon search sequences and hunt items in order. First, just after sunset, find the galaxies M77 and M74. Last, just before dawn, catch the globular clusters M72 and M30 plus the asterism M73. The date of the Messier Marathon is always on the new moon closest to the vernal equinox. During the night you can rest and turn on while you wait for the next batch of Messier objects to pick up. Or enjoy other beautiful deep sky objects to keep you busy all night.
A bit of history
Ironically, Charles Messier never intended to compile a list of deep sky objects. Since Messier was a comet hunter, he began cataloging nebulae, which are often mistaken for comets. In short, these nebulous objects also appear as visually diffuse bodies, just like a comet. Comets were important in the 18th century because astronomers tracked their paths. This data has been successfully verified Newton’s theory of universal gravitation. Messier is credited with the discovery of 13 comets. However, Messier is remembered more for his Messier Catalog than for his comet discoveries.
Of the 110 Messier objects, 41 are Messier observations. The first edition of the catalog was published in 1774 and contained only 45 items. Subsequent editions expanded the list and another edition appeared in 1781 bringing a total of 103 objects. Astronomical writer Camille Flammarion – also a Frenchman – added object number 104 from Messier’s notes. Finally, some astronomers published a revised version in 1967, bringing the total up to 110 Messier objects.
Messier lived and worked in Paris, France at lat 49 degrees north. So he could only observe the entire northern celestial hemisphere and about half of the southern sky. This in turn explains why some notable southern objects, such as the globular star cluster Omega Centauri, are not on the list. Furthermore, the bright nebula Eta Carinae is not a Messier object. Also not included in the list is the very obvious Perseus binary in the northern celestial hemisphere.
Messier 45, Pleiades
Messier 31, the Andromeda Galaxy
Messier 13, the Great Globular Cluster in Hercules
Messier 42, the Orion Nebula
Useful links to Messier objects
A nice reference for stargazers with a telescope is a book called Deep-Sky Companions: Messier Objectsnow in its second edition. Written by renowned amateur astronomer Stephen James O’Meara, this book contains over 100 pencil drawings illustrating the true visual appearance of Messier objects as viewed from Hawaii through a small refracting telescope.
NASA has a beautiful photo gallery of some of the Messier objects from Hubble Space Telescope.
Bottom line: Messier objects are a list of 110 star clusters, nebulae, and galaxies compiled by comet hunter Charles Messier in the 1700s.
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