M9 · globular cluster

Messier 9

Messier 9 or M9 is a globular cluster in the constellation of Ophiuchus.

RA17h 19m 11sDec−18° 30' 58"

Image: NASA / GSFC. Source: GSFC via images.nasa.gov.

Identity & coordinates

Identification

Primary designation: M9
All designations: M9 · NGC 6333
Object type: Globular Cluster
Constellation: Ophiuchus
Best viewing: Summer

Coordinates & physical

Right ascension (J2000): 17h 19m 11s
Declination (J2000): −18° 30' 58"
Apparent magnitude (V): —
Distance: —

III

Visibility tonight

The science

Messier 9 or M9 is a globular cluster in the constellation of Ophiuchus. It is positioned in the southern part of the constellation to the southwest of Eta Ophiuchi, and lies atop a dark cloud of dust designated Barnard 64. The cluster was discovered by French astronomer Charles Messier on June 3, 1764, who described it as a "nebula without stars". In 1783, English astronomer William Herschel was able to use his reflector to resolve individual stars within the cluster. He estimated the cluster to be 7–8′ in diameter with stars densely packed near the center.

Summary adapted from Wikipedia · CC-BY-SA-4.0