Messier 109 (also known as NGC 3992) is a barred spiral galaxy approximately 41 million light-years away in the constellation Ursa Major. M109 can be seen southeast of the star Phekda (? UMa).
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 are not official, but in later years the additions became pretty widely accepted. David Levy mentions the modern 110 object catalog while Sir Patrick Moore gave the original to 104 but has M105-M109 listed as an addendum. By the late 1970s all 110 objects are commonly used among astronomers as they still are today.
