Astrophotography by Anthony Ayiomamitis

Deep Sky Object Image Gallery

Open star clusters are widely distributed in our galaxy and represent a loose collection of stars which number from a few dozen to a few hundred stars and are weakly-held gravitationally. Perhaps the three most famous such open clusters are the Pleiades (M45) in Taurus, the Beehive (M44) in Cancer and the double cluster in Perseus. They are all characterized with a handful of hot and white prominent stars and nebular material surrounding these stars.

Note: Open cluster NGC 6871 in Cygnus depicted below is a cluster comprised of less than 50 member stars which are interspersed and well detached from the background sky. The cluster is dominated by a pair of double star systems comprised of SAO 69402 (mag 6.77) and SAO 69403 (mag 7.36) for the northern pair and SAO 69405 (mag 7.86) and SAO 69404 (mag 8.86) which make up the southern pair. The cluster spans 20 arc-minutes in diameter and lies 5135 light-years away. NGC 6871 has been studied fairly intensely owing, in part, to the presence of eclipsing binaries (ex. V453 Cyg). Its distance has been estimated to be around 5135 light-years while its age is a mere 9.1 million years old. NGC 6871 is surrounded by nebulosity including LBN 180 to the north, LBN 182 to the east and LBN 179 and 174 to the south and southwest. The small patch of nebulosity near the bottom right corner is the nebula GN 20.03.0. The cluster is best observed using low magnifications (50-100x) during summer when it is directly overhead and can be found to lie just to the south of 27-Cyg (mag 5.38). NGC 6871 was discovered by Friedrich Georg Wilhelm von Struve (1793-1864) in 1825.

Note: SAO 69402 (mag 6.77) referred to above is also the brightest Wolf-Rayet star (WR 133) visible in the northern hemisphere!

Please click on the image below to display in higher resolution (1200 x 950)

Image Details
NGC 6871 - Open Cluster in Cygnus
Imaging Details
NGC Number:
6871

Common Name(s):
N/A

Other Designations:
Cr 413, OCL 148

Object Type:
Open Cluster

Object Classif:
II 2 p n

Constellation:
Cygnus

RA / Dec:
20h 06m 00s /
35° 46' 38"


Distance:
5135 light-yrs

Object Size:
20' x 20'

Magnitude:
5.2
Date:
July 11, 2010
02:35 - 4:40 UT+3


Location:
Athens, Greece

Equipment:
AP 160 f/7.5 StarFire EDF
AP 1200GTO GEM
SBIG ST-10XME
SBIG CFW10
SBIG LRGB + IR-block


Integrations:
Lum :  030 min (10 x 3 min)
Red :  030 min (05 x 6 min)
Green :  030 min (05 x 6 min)
Blue :  030 min (05 x 6 min)
Binning :  1x1 (Lum),  1x1 (RGB)

Image Scale:
1.16" per pixel

Temperatures:
Ambient : + 19.0 ° C
CCD Chip : - 12.5 ° C

Software:
CCDSoft V5.00.195
CCDStack V1.6.0.5
eXcalibrator V1.0.3.0
Aladin V6
Photoshop CS2