Fighting light pollution.....
The Double Cluster is the common name for the naked-eye open clusters NGC 869 and NGC 884 which are close together in the constellation Perseus. NGC 869 and NGC 884 both lie at a distance of 7500 light years. NGC 869 has a mass of 3700 solar masses and NGC 884 weighs in at 2800 solar masses; however, later research has shown both clusters are surrounded with a very extensive halo of stars, with a total mass for the complex of at least 20,000 solar masses. Read more.
|Name and aliases||NGC 869||NGC 884|
|Common names||h Per Cluster, h Persei Cluster||chi Per Cluster, chi Persei Cluster, khi Per Cluster|
|Type||Open (galactic) Cluster||Open (galactic) Cluster|
|Coordinates||02:18:57.84 +57:08:02.4||02:22:20.16 +57:08:56.4|
|Radial velocity||-38.9 km/s||-43.5 km/s|