Messier 44, Praesepe, Beehive Cluster

Messier 44
Messier 44: Section of DSS (POSS2 Red) from CDS Aladin Lite [147]

History

The open star cluster Messier 44 in the constellation Cancer is also called «Beehive Cluster» or «Praesaepe». Because it can easily be seen as a misty spot with the naked eye even under modest observation conditions, it has been known for many centuries. For example, Hipparchus (130 B.C.) called it a «little cloud». He included M 44 as a «cloudy star» in his star catalog. [Jones] It was not until 1610 that Galileo Galilei discovered with the telescope he had built that it was a collection of stars. [4]

❝ Am Firmament funkeln die Sterne.
Die winzigen Lichtchen, ich sehe sie gerne.
Gern seh' ich auch die Nebel dort oben
und Dunkelwolken zu Netzen verwoben,
ferne Milchstrassen, 'nahe' Planeten,
schnuppende Sterne und hübsche Kometen.
Nur eines darf mir gestohlen werden:
planetarische Nebel hier unten auf Erden. ❞

Physical Properties

Baade estimates the age of M 44 to be around 400 million years, other data go up to 660 million years. This star cluster is significantly older than the Pleiades (M 45). Its mean density of 1.5 stars per cubic parsec is very low, in the center it reaches 13.8 stars per cubic parsec (Wallenquist).

Trümpler gives the diameter of the star cluster as almost 6 degrees, including all faint stars; Its classification of the cluster is I, 2, r. The distance from M 44 is currently given as about 180 parsec.

«Revised New General Catalogue and Index Catalogue» Dr. Wolfgang Steinicke, 2021 [277]
DesignationNGC 2632
TypeOCL (II2m)
Right Ascension08h 40m 24.0s
Declination+19° 40' 12"
Diameter70.00 arcmin
Photographic (blue) magnitude3.5 mag
Visual magnitude3.1 mag
Dreyer DescriptionPaesepe Cancri
IdentificationM 44, OCL 507, Praesepe, Beehive cluster

Galaxies behind M 44

Behind the open star cluster are a number of galaxies, most of which appear to us to be small and faint. For this reason they are only listed here for the sake of form.

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
NameRA [hms]Dec [dms]mTypeDim [']Btot [mag]HRV [km/s]PA [°]
NGC 262408 38 09.6+19 43 33S.6 x .514.6
NGC 262508 38 23.1+19 42 59.3 x .315.34510
IC 238808 39 58.2+19 38 21 x 15.7
NGC 263708 41 10.1+19 41 17 x 15.4
NGC 2643, IC 239008 41 46.1+19 42 15 x 15.6
NGC 264708 42 40.0+19 39 12C x 15.1

Where do you find the swarm of bees?

The constellation Cancer is located between Leo and Gemini. If you lengthen the distance between the two bright twin stars Castor and Pollux by about three times to the southeast, you can see M44 with the naked eye. not far from the 4 mag bright star δ Cancri (Asellus Australis). The close-up is used to identify the small, faint galaxies.

Chart Messier 44
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

Naked Eye, Binocular, RFT: With its size of a good one and a half degrees (three times the full moon diameter), the star cluster itself is best seen in binoculars and small telescopes with a large field of view. Then a dense, impressive cloud of bright stars appears.

400mm Aperture: But M 44 also has a lot to offer for the observer with a large telescope aperture, because behind the open star cluster there are a number of galaxies. Almost all of them can be detected with an aperture of 400 mm under an average sky (~6 mag). However, the presence of the bright stars of M44 makes observation more difficult, as is the case with Leo I.

NGC 2624
NGC 2625
PGC 24284400x: small, round, at the limit
PGC 24335not yet proven
IC 2388400x: round, even surface at the limit
UGC 4526400x: even surface, elongated with position angle 230°
NGC 2637not yet proven
NGC 2643400x: large, round surface
NGC 2647226x: small, round surface, bright, compact core visible with averted vision

Frank H. Leiter

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
144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); cdsarc.unistra.fr/viz-bin/cat/VII/119 (2021-02-18)
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
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)