Messier 109 [SEP] discoverer or inventor
Messier 109
Messier 109 (also known as NGC 3992) is a barred spiral galaxy exhibiting a weak inner ring structure around the central bar approximately away in the constellation Ursa Major. M109 can be seen southeast of the star Phecda (γ UMa).
History.
Messier 109 was discovered by Pierre Méchain in 1781. In 1783 Charles Messier catalogued NGC 3992 as his 109th object.
Between the 1920s through the 1950s, it was considered that Messier objects over 103 were not official, but in later years the
as the Messier catalogue, the NGC (New General Catalogue), the IC (Index Catalogue), the CGCG (Catalogue of Galaxies and of Clusters of Galaxies), the MCG (Morphological Catalogue of Galaxies) and UGC (Uppsala General Catalogue of Galaxies). All of the well-known galaxies appear in one or more of these catalogues but each time under a different number.
For example, Messier 109 is a spiral galaxy having the number 109 in the catalogue of Messier, and also having the designations NGC