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NGC 2099 (3,984 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




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Auriga Salt-and-Pepper

NGC 2099, Cl Collinder 75, C 0549+325, COCD 82, Messier 37, Auriga Salt-and-Pepper, h 369, GC 1295

RA: 05h 52m 19s
Dec: +32° 33′ 12″

Con: Auriga
Ch: MSA:134, U2:98, SA:5

Ref: SIMBAD, Collinder (1931), DAML02, Archinal&Hynes (2003)

(reference key)

Type: open cluster, 12r

Mag: B=6.19, V=5.6

Size: 14′
PA: ?

Historical observations

Messier, Charles (1764)

This cluster was discovered by Messier in 1764.

William Herschel (c.1784)

In the Appendix to the 1912 'Scientific Papers of Sir William Herschel' this object is described as "1782, November 4, 20 feet telescope, is an astonishing number of small stars with 227; they are almost all of the 2nd or 3rd classes. I seen no kind of nebulosity in the spot. With 460 the whole is resolvable into stars without nebulosity. 1783, August 24, a useful, coarse step; it will serve to learn to see nebulae, becuase it contains many small stars mixed with others of various magnitudes, many of which are not to be seen without great and long attention."

Webb, T.W. (1893)

In the 5th edition of Webb's Celestial Objects for Common Telescopes it is described as "Smyth calls this 'a magnificent object;' the whole field being strewed, as it were, with sparkling gold-dust; and the group is resolvable into about 500 stars, from 10 to 14th mag, besides the outliers. Even in smaller instruments extremely beautiful, one of the finest in its class. Gaze at it well and long. Knott notices a brighter star near centre, Burton: ruby: 10th mag; Espin: 9th mag, pale red. All the stars in the mass must be nearly at the same distance from us, and consequently their real sizes must be different. The aspect of the Nubecula Major in the southern hemisphere convinced John Herschel of this; it is ocular proof of the incontrovertible,. though long discredited fact, that the apparent brightness of stars has very little connection with their distance from earth. E. of Rosse, wonderful loops and curved lines of stars, first remarked by d'Arrest."

Birr Castle/Lord Rosse

Burnham calls it remarkable, bright, very rich, much compressed with 150 stars of 9th magnitude and fainter in a 20' area. He says it is a "superb cluster for telescopes of all sizes, usually considered the finest of the three Messier open clusters in Auriga, and apparently first observed by Messier himself in 1764. It will probably look like a nebula in instruments smaller than 1.5-inch aperture, but in anything larger than a 2-inch, some of the individual stars will be seen easily. 'A diamond sunburst' as C E Barns described it, this striking cluster is a virtual cloud of glittering stars. 'Even in small instruments', says T W Webb, 'it is extremely beautiful, one of the finest of its class.' The great observer Smythe calls it 'a magnificent object, the whole field being strewed as it were with sparkling gold-dust; it resolves into infinitely minute points of lucid light'. The Earl of Rosse commented on the 'wonderful loops and curved lines of stars', which seem also to be a feature of other clusters, as M35 in Gemini, for example. ... the cluster also contains at least a dozen red giants. The brightest of these has a visual magnitude of about 9.5 and stands out near the cluster center 'like a ruby on a field of diamonds.' "

Lassell, W. (1854)

Lassell, W. (1854) Observations of the nebula of Orion, made at Valletta, with the twenty-foot equatorial. Memoirs R.A.S., 23, 53-62.

Perhaps third unidentified object discussed on p.59?

Published comments

Raab, S. (1922)

Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.

Discussed, based of F-A plates.

Trumpler, R.J. (1928)

Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 24' and the class as 1 1 r.

Doig, P. (1925)

Doig, P. (1925) Notes on the nebulae and clusters in Webb's 'Celestial Objects for Common Telescopes' (Sixth edition, Vol.ii). Part I. M.N.R.A.S., 35(5), 159.

Burnham's Celestial Handbook

M37 combines the size and richness of M38 with the star brightness of M36. It is nearly 4 East-Southeast of M36. Burnham notes that M37 appears as a rich, somewhat triangular hive of stellar activity with a number of coloured stars. The cluster comprises some 150 stars in an area 24' across.

Sanford (1989) Observing the Constellations

Sanford calls it "one of the finest open clusters in the sky .. there are a number of yellowish or reddish giant stars in this group."

Melotte, P.J. (1915)

A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.

Bailey, S.I. (1908)

"! cluster; fiarly condensed; regular; almost globular."

Bailey, S.I. (1908) A catalogue of bright stars and nebulae. Ann.Harv.Coll.Obs., 60(8), 199.

Vorontsov-Velyaminov, B. (1925/1926)

Vorontsov-Velyaminov, B. (1925) "Catalogue of integrated magnitudes of star clusters", Astron. Nach. 226.195. Comparing the brightness of the cluster with the extrafocal images of stars, he estimates the magnitude as 6.47.

Doig, P. (1926)

Doig, P. (1926) "A Catalogue of Estimated Parallaxes of 112 Nebulae, Open clusters and Star Groups", Vol 36 (4), p 107-115.

"dense regular cluster, condensed at centre." He gives the approx. diameter as 30 arcmin.

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a 6.0 mag open cluster.

Modern observations

Hartung, E.J. (1968) Astron.Obj.South.Tel

Hartung comments that "small apertures give this beautiful rich cluster a nebulous appearance as remarked by Messier... it consists however only of stars extending with outliers about 25' across. An orange star is near the centre, which is considerably concentrated, with a lobed pattern and radiating arms, the whole effect very fine."

Harrington, Phil

Harrington calls it an "exceedingly rich open cluster of about 150 stars scattered across half a degree of sky. Most shine between 10th and 13th magnitude. Although the smallest amateur instruments show M37 as an unresolved swarm of hazy stardust, the cluster puts on a dazzling show for 6-inch and larger scopes. Such instruments reveal hundreds of fainter points crammed tightly against a striking backdrop of field stars. One of M37's stars, a 9th mag stellar ember, beams a radiant orange-red. Subtle tinges of colour can be glimpsed in some of the fainter cluster members. Perhaps Thomas W. Webb summed up this cluster best of all ... 'Even in small instruments, [M37 is] extremely beautiful, one of the finest of its class. Gaze at it well and long.' "

Tom Lorenzin

Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "5.6M; 24' diameter; very beautiful! very populous with 150-plus members; dark gap in SW reaches."

Raasch, Rick (1993)

Rick Raasch writes in "The Focal Point", Volume 6, No. 3 (1993) "M37 This is probably the most populous of the Messier objects in this constellation. I estimate there to be over 150 stars in this impressive, tightly concentrated star cluster. It is about 20-25' in diameter, and is dominated by a bright orange tinted star at its center."

Callender, John

Observer: John Callender (e-mail: jbc@west.net, web: http://www.west.net/~jbc/) Instrument: 50-mm binoculars Location: Carpinteria, CA, USA Light pollution: light Transparency: good Seeing: poor Time: Mon Feb 3 05:50:00 1997 UT Obs. no.: 45

"Midway in size between M38 and M36; a medium-brightness fuzzy patch with a brighter center."

Gross, Todd (IAAC)

Observer: Todd Gross; Your skill: Intermediate ; Date and UT of observation: 11/5/97 0820 GMT; Location & latitude: 22 miles west of Boston, Ma. 42.3N; Site classification: Suburban; Limiting magnitude (visual): 5.2 (estimated) 5.2 (est) in vicinity of object; Seeing (1 to 10 - worst-best): 8 ; Moon up (phase?): No; Weather: Clear; Instrument: 90mm Flourite Apochromatic f/9; Magnifications: 54x; Filters used: none; Object: M37; Constellation: Auriga; Object data: Open Cluster; Personal "rating" (at this aperture): A;

" This is fabulous at this aperture! M37 is a large, extremely dense open cluster of dim stars, with a red, dim central star. At 90mm, the red color is barely noticeable on the central star, and some of the dimmer stars are not apparent as in larger scopes. However, the impression is almost exactly the same. That is.. a perfectly circular dense cluster swimming in fairly dim stars, but of equal magnitude!"

Gross, Todd (IAAC)

Observer: Todd Gross; Your skill: Intermediate ; Date and UT of observation: 09/05/97 0813GMT; Location & latitude: 22 miles west of Boston, Ma. 42.3N; Site classification: Suburban; Limiting magnitude (visual): 5.2 (estimated) 4.8 (est) in vicinity of object; Seeing (1 to 10 - worst-best): 4; Moon up (phase?): No; Instrument: 16" Newtonian-dob w. 96/99% coatings; Magnifications: 125x (15mm Panoptic); Filters used: none; Object: M37; Constellation: ; Object data: Open cluster;

"Large, fully resolved open cluster, but dense. Could have used a bit less magnification for a better view. Hundreds of stars of equal magnitude with the exception of one ruby red, very slightly brighter star, near dead-center. Slightly star-like in shape. Extremely beautiful."

Coe, Steve (IAAC)

Observer: Steve Coe; Your skills: Advanced (many years); Date/time of observation: Feb 25, 1995; Location of site: Sentinel, Arizona (Lat +32, Elev 1500); Site classification: Rural; Sky darkness: 7/10 1-10 Scale (10 best); Seeing: 6/10 1-10 Seeing Scale (10 best); Moon presence: None - moon not in sky; Instrument: 13" F/5.6 Bigfoot German Equatorial Mount; Magnification: 150X, 220X; Filter(s): none

This terrific cluster is easy in the 11X80 finderscope and show up as a bright area in the Winter Milky Way that is elongated 2X1 in PA 0 degrees. In the 13" at 150X this is a magnificent object, it is very bright, large, very rich and compressed. I counted 146 stars involved, many in beautiful chains of stars that are cut by dark lanes winding through the cluster. There is a nice dark orange star of 10th magnitude on the north side in a dark area. Raising the power to 220X resolves many more very faint stars, lots of pairs included within the cluster. The higher power also really accentuates the dark lanes that are so prominent in this stunning cluster.

Brian Skiff

6cm - rich cloud elong in pa40. res but density precludes counting, but in neighborhood of 30 *s. note br * in center.

7cm - exquisite cl @ 30x, well res and w/o haziness. m9.5 `cen *' not consp. outliers reach to m9 * immed N of m7 * due S of cl. vgood @ 50x, lots o' stars---well over 100, est 150 anyway. BS, 26Nov1992, Anderson Mesa.

15cm - fantastic. almost ident w/M11, even has br cen *. glorious @ 67x and 160x. BS, 5Sep1970, FtL.

- compact cloud of f *s w/shining m7 cen *.

- broken down view of M22 or omega Cen. two dk lanes through center, on E and S about 4'x1'.

- third and best of Aur big three ocs, although not so much better than M38 to outclass it. 50' diam, stragglers reaching to m7 yel-or * SW. main body 30' across, core 5'. 140x shows 80 *s just in core, 200 in 30' area. 50x/80x give impression that most *s nrly same brtness---ye olde giant branch. core broken into big clumps of *s w/consp dk lanes running among them. rel blank area of sev connected ~circ lobes SE of `core.' m9.0 cen * is on E side of core, seems inconsp w/averted vis, but stands out with direct vis. BS, 4Dec1989, Anderson Mesa.

25cm - more than 200 *s, m10-11. 40' diam. vrich.

- vbr, well res @ any power. br cen * more consp @ lox most *s m10-11, 200 total, outliers to 50'. core 8', non-circ, flattened on SE w/empty area. cen * only cream-yel despite lg B-V. BS, 6Oct1981, Anderson Mesa.

30cm - fills 149x/22' fld w/broad concen core. too many *s to count. remarkably, most *s are about same mag. lg 5' dk area on SSE side w/one * in it. elong not obvious at this aperture. CBL, Roof.

Danie L. Cronje


Danie Cronje, observing with 10x50 binoculars, notes "appears mostly like a glow, but can resolve stars."

Contemporary observations

Auke Slotegraaf

1994 January 27

1994-01-27, Die Boord, tripod-mounted 11x80's Very low on horizon, some smoke. Fainter than M36; irregular dim patch.

Magda Streicher

1999 January 18

Open Cluster, Auriga, 5h 49m 0s, +32 33

Telescope: Meade 12-inch - 40mm wide-angle eyepiece.

Date: 18th January 1999.

Exceptional open cluster with a lot of detail. Large and bright - with mixed magnitude stars in cartwheel shape with curls and lines running out like spouting arms from a relatively compact middle. Dark lanes randomly visible. Striking orange star in the middle. Truly a very beautiful open cluster.

Tom Bryant

2006-10-29 03:00:00

Observing site: Little Tycho Observatory

Telescope: C-8

[5h 52m 24s, 32� 33m 0s] The richest, but faintest of the Auriga Messier clusters. Overall, a beautiful cluster that would be better served by darker skies.

Pierre de Villiers

2016 February 06, Saturday

Location: Bonnievale SSP

Telescope: 200-mm f/5 Skywatcher, Delos 8-mm ep (0.57-deg fov)

M 37 open cluster with intricate structure; square 'body' with W and SE extensions. Fairly dim. m = 6; size 17-arcmin.

Favourite lists

Lacaille's catalogue

The Messier objects

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