by Anthony Ayiomamitis
The open cluster NGC 6883 in Cygnus depicted above is comprised of approximately 30 member stars which are not very well detached from the background sky owing to the fact the cluster is in a very rich section of Cygnus and which happens to be also embedded within the eastern end of the nebulosity associated with LBN 182. As indicated by the image above, the cluster is dominated by a handful of bright stars (mag 7-9) including a tight double at its core (mag 9.41 and 9.73) as well as a bright pair of bright red giants to the west (HD 191783, mag 9.25, B-V=3.31 and SAO 69548, mag 8.92, B-V=2.43). The cluster is generally widely dispersed and easily lost in the deep background sky. NGC 6883 spans 15 to 35 arc-minutes in diameter (depending on the source) and is estimated to be 14-16 million years-old while a distance is not available in the academic literature. The small reflection nebula left of center is rather obscure and is simply known as GN 20.10.7. The cluster is best observed using low magnifications (50-100x) during summer when it is directly overhead and a few degrees west of Sadr. NGC 6883 was discovered by John William Herschel (1792-1871) in 1828.
Technical Details:
Date: July 12-13, 2010 @ 23:45 - 01:55 UT+3
Location: Athens, Greece (38.2997° N, 23.7430° E)
Equipment: AP 160 f/7.5 StarFire EDF, AP 1200GTO GEM, SBIG ST-10XME, SBIG CFW10, SBIG LRGB filters
Integrations: LRGB @ 30:30:30:30 using 3-/6-min subs, 1x1 binning, 1.17"/pixel, -12.5d C
Further details are available here.