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 1981 illustrated below lies 0.5 degrees north NGC 1977 (Running Man Nebula) and slightly over one degree north of M42-M43 (Orion Nebula). It is comprised of approximately 20 member stars lossely scattered across a field measuring 0.5 by 0.5 and with at least eight bright stars ranging in magnitude from 6.5 to 8.1 dominating the field of view. The cluster is approximately 1,200 light-years away with an apparent diameter of 10 light-years across. Although no estimates as to the age of this cluster exist, other clusters within Orion (NGC 1976 and Collinder 69-70) have been dated to be only 10 to 13 million years old. The nebulosity in the lower portion of the cluster is from the reflection/emission nebula NGC 1977. The cluster is best viewed during winter and can easily be located using binoculars just to the south of Orion's belt.

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

Image Details
NGC 1981 - Open Cluster in Orion
Imaging Details
NGC Number:
1981

Common Name(s):
N/A

Other Designations:
Cr 73, OCL 525

Object Type:
Open Cluster

Object Classif:
III 3 p n

Constellation:
Orion

RA / Dec:
05h 35m 10s /
-04 25' 30"


Distance:
1,200 light-yrs

Object Size:
25' x 25'

Magnitude:
4.2
Date:
Nov 00-00, 2012
22:15 - 00:20 UT+2


Location:
Athens, Greece

Equipment:
AP 305/f3.8 Riccardi-Honders
AP 1200GTO GEM
SBIG ST-10XME
SBIG CFW10
SBIG LRGB filters
Baader H-a 7 nm


Integrations:
H-a :  000 min (00 x 10 min)
Lum :  030 min (30 x 01 min)
Red :  030 min (10 x 03 min)
Green :  030 min (10 x 03 min)
Blue :  030 min (10 x 03 min)
Binning :  1x1 (Lum),  1x1 (RGB)

Image Scale:
1.21" per pixel

Temperatures:
Ambient : + 00.0 C
CCD Chip : - 00.0 C

Software:
CCDSoft V5.00.201
CCDStack V1.6.0.5
eXcalibrator V1.0.3.0
Aladin V6
Photoshop CS2