Messier object

|alt=Painting of Charles Messier The first edition of 1774 covered 45 objects (M1 to M45). The total list published by Messier in 1781 contained 103 objects, but the list was expanded through successive additions by other astronomers, motivated by notes in Messier's and Méchain's texts indicating that at least one of them knew of the additional objects. The first such addition came from Nicolas Camille Flammarion in 1921, who added Messier 104 after finding a note Messier made in a copy of the 1781 edition of the catalogue. M105 to M107 were added by Helen Sawyer Hogg in 1947, M108 and M109 by Owen Gingerich in 1960, and M110 by Kenneth Glyn Jones in 1967. M102 was observed by Méchain, who communicated his notes to Messier. Méchain later concluded that this object was simply a re-observation of M101, though some sources suggest that the object Méchain observed was the galaxy NGC 5866 and identify that as M102. Messier's final catalogue was included in the [Knowledge of the Times for the Year 1784], the French official yearly publication of astronomical ephemerides. ==Observations==

The Messier catalogue comprises nearly all of the most spectacular examples of the five types of deep-sky object – diffuse nebulae, planetary nebulae, open clusters, globular clusters, and galaxies – visible from European latitudes. Furthermore, almost all of the Messier objects are among the closest to Earth in their respective classes, which makes them heavily studied with professional class instruments that today can resolve small and visually significant details in them. A summary of the astrophysics of each Messier object can be found in the Concise Catalog of Deep-sky Objects. Since these objects could be observed visually with the relatively small-aperture refracting telescope (approximately 100 mm ≈ 4 inches) used by Messier to study the sky from downtown Paris, they are among the brightest and thus most attractive astronomical objects (of the class popularly called deep-sky objects) observable from Earth, and are popular targets for visual study and astrophotography available to modern amateur astronomers using larger aperture equipment. In early spring, astronomers sometimes gather for "Messier marathons", when all of the objects can be viewed over a single night. == Messier objects ==

== Star chart of Messier objects ==

depicting the Messier objects plotted on a rectangular grid representing right ascension and declination ==See also==