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: The open cluster NGC 7789 in Cassiopeia is a bright and richly populated cluster comprised of approximately 300 member stars which are evenly distributed and well detached from the background sky. This cluster lies at a distance of 7620 light-years away with an apparent diameter of 25'. As indicated by the various red giants in the image below, the cluster is advanced in age and which has been estimated to be approximately 1.6 billion years-old. NGC 7789 was discovered by Caroline Herschel in 1783. It lies a few degrees west of Caph (-Cas, mag 2.26) and is best observed using low magnifications during late fall and winter when it is placed directly overhead when looking due northeast.

Please click on the image below to display in higher resolution (1200 x 900)

Image Details
NGC 7789 - Open Cluster in Cassiopeia
Imaging Details
NGC Number:
7789

Common Name(s):
Screaming Skull

Other Designations:
Cr 460, OCL 269

Object Type:
Open Cluster

Object Classif:
II 2 r

Constellation:
Cassiopeia

RA / Dec:
23h 57m 26s /
56 44' 00"


Distance:
7620 light-yrs

Object Size:
25' x 25'

Magnitude:
6.7
Date:
Dec 11, 2007
18:45 - 21:00 UT+2


Location:
Athens, Greece

Equipment:
AP 160 f/7.5 StarFire EDF
AP 1200GTO GEM
SBIG ST-2000XM
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)
Dark :  135 min (15 x 3+6 min)
Flat :  ~ 24,500 ADU
Binning :  1x1 (Lum),  1x1 (RGB)

Temperatures:
Ambient : + 09.4 C
CCD Chip : - 20.0 C

Software:
CCDSoft V5.00.182
AIP4Win V2.1.19
Photoshop CS2