NGC 6882/6885 is an open cluster in the faint constellation of Vulpecula that can just about be seen with the naked eye, is easy with binoculars and has up to 40 stars visible through telescopes. This object has somewhat of a confusing history. In September 1784, William Herschel discovered two open clusters, NGC 6882 and NGC 6885. He subsequently catalogued them, but with virtually identical descriptions. Since no cluster exists that matches the location and description of NGC 6882, many astronomers believe that Herschel made a mistake and simply repeated his observation. However, the story doesn't end here. Adding to the confusion is a fainter, smaller and less rich cluster, Collinder 416, that's positioned at the northwestern edge of NGC 6885. Some astronomers believe this to be NGC 6882.
NGC 6882/6885 is grouped around the brightest member star, 20 Vul (mag. +5.9). Located 1.5 degrees northeast of NGC 6882/6885 is 23 Vul, which at magnitude +4.5 is the second brightest star in the constellation. Positioned 9 degrees west-northwest of the cluster is the beautiful double star Albireo (mag. +2.9) in Cygnus.
NGC 6882/6885 is faintly visible to the naked eye under dark skies, appearing as a hazy patch of light. Binoculars easily reveal 20 Vul, although on initial glance the cluster may be missed due to the glare of the star. On further inspection the main members of the grouping are resolvable. Surrounded them is a misty glow with the centre of the cluster appearing loose. A small scope reveals more members with larger scopes revealing up to 40 stars. In total, NGC 6882/6885 is spread over 20 arc minutes of sky.
NGC 6882/6885 has a combined mag. of +5.5. The nearby smaller fainter cluster Collinder 416 (Cr 416) shines at mag. +8.1 and spans 8 arc minutes. To many observers, this region appears as just one loose star grouping. NGC 6882/6885 is a very old cluster with an estimated age of 1.4 billion years. It's about 2,000 light-years distant from Earth and is listed as number 37 in the Caldwell catalogue. The cluster is best seen from northern locations during the months of July, August and September.
NGC 6882 / NGC 6885 Data Table
|NGC||6882 / 6885|
|Object Type||Open Cluster|
|RA (J2000)||20h 11m 56s|
|DEC (J2000)||26d 29m 20s|
|Apparent Size (arc mins)||20 x 20|
|Age (years)||1.4 Billion|
|Number of Stars||40|
|Notable Feature||Quesions remain regarding if NGC 6882 and NGC 6885 are indeed the same item|