Open Cluster Messier 67

Messier 67
Messier 67: Section of STScI Digitized Sky Survey [147]

History

The open star cluster was discovered before 1779 by Johann Gottfried Köhler, who described it as «a rather conspicuous nebula with an elongated shape near Alpha von Cancer». The fact that it was unable to resolve any single stars provides information about the imaging quality of its telescope. Independently of Köhler, the star cluster was discovered again on April 6, 1780 by Charles Messier. He too believed he saw a nebula and wrote about it: «A cluster of small stars with a nebula below the southern claw of Cancer. Position determined by α [Cancri].» [217, 281]

Physical Properties

M 67 is an open star cluster of the Trumpler type II2m and one of the oldest known of this type. The age is estimated to be 10 billion years. It contains about 500 stars, measures about 12 light years in diameter, and is about 2500 light years away from us. A special feature of this cluster is the great distance of 1500 light years outside the plane of our galaxy. Most of the open star clusters are found along the galactic plane. [4, 196]

«Revised New General Catalogue and Index Catalogue» Dr. Wolfgang Steinicke, 2021 [277]
DesignationNGC 2682
TypeOCL (II2m)
Right Ascension08h 51m 18.0s
Declination+11° 49' 00"
Diameter25.00 arcmin
Visual magnitude6.9 mag
Dreyer Description! Cl, vB, vL, eRi, lC, st 10…15
IdentificationM 67, OCL 549

Finder Chart

M 67 is located in the constellation Cancer, about 1.75° west of the star Acubens (α Cancri). It is best observed from December to May.

Chart Messier 67
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

4«Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System» by Robert Burnham; Dover Publications, Inc.; Voume I: ISBN 0-486-23567-X; Volume II: ISBN 0-486-23568-8; Volume III: ISBN 0-486-23673-0
147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
217The Messier Catalog (SEDS); messier.seds.org (2021-01-01)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
281«Catalogue Nébuleuses et des Amas D'Étoiles» Observées à Paris, par M. Messier, à l'Observatoire de la Marine, hôtel de Clugni, rue des Mathurins. «Connoissance des temps ou connoissance des mouvements célestes, pour l'année bissextile 1784 » Page 227; gallica.bnf.fr/ark:/12148/bpt6k6514280n/f235 (2021-02-21)