Open Cluster Messier 93

Messier 93
Messier 93: Section of the STScI Digitized Sky Survey [147]

History

Charles Messier discovered his number 93 on March 20, 1781 and noted: "A cluster of small stars, without nebula, between the big dog and the bow of the ship." [281]

Physical Properties

M 93 is an open cluster of the Trumpler type IV1p and contains about one hundred stars, spread over an area of about 22 arc minutes. At an estimated distance of around 3600 light years, it must be around 20 to 25 light years long. The brightest stars in the main sequence in the cluster are of the spectral type B9, which suggests that the cluster is about 100 million years old. [196]

«Revised New General Catalogue and Index Catalogue» Dr. Wolfgang Steinicke, 2021 [277]
DesignationNGC 2447
TypeOCL (IV1p)
Right Ascension07h 44m 30.0s
Declination-23° 51' 24"
Diameter10.00 arcmin
Visual magnitude6.2 mag
Dreyer DescriptionCl, L, pRi, lC, st 8…13
IdentificationM 93, OCL 649, ESO 493-SC7

Finder Chart

The open star cluster is located in the constellation Puppis about 1.5 degrees northwest of the 3.3 mag bright star Asmidiske (ξ Puppis). The best time to observe is around January, when the constellation is highest above the southern horizon at night.

Chart M 93
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

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)
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)