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RA: 07h 16m 59.3s
Dec: +13° 44′ 59″
Ch: MSA:201, U2:184, SA:12
Ref: SIMBAD, Collinder (1931), DAML02, NGC/IC, Archinal&Hynes (2003)
Type: open cluster, 22m
Mag: B=?, V=9.7
NGC 2355. See NGC 2356.
Synonyms: H VI-006
Discovered in 1785 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a cluster of stars of various sizes, pretty much compressed in the middle, pretty rich."
Trumpler (Lick Obs Bul, Vol 14, No. 420) gives the diameter as 7' and the class as 1 2 m.
Photo Index by Jim Lucyk: Observer's Guide (Astro Cards) 11-12/88 p31.
A catalogue of star clusters shown on Franklin-Adams chart plates. Mem.R.A.S., 60(5), 175-186.
Raab, S. (1922) A research on open clusters. Lund Medd. Astron. Obs. Ser. II, 28, 1.
Discussed, based of F-A plates.
The RNGC (Sulentic and Tifft 1973) notes that this is a 9.5 mag open cluster.
Listed by the Herschel Club, described as "very rich cluster, some 70 stars counted, small and tightly packed, faint, situated near a 6th mag star in field. 6-inch, 48x."
Tom Lorenzin, in the electronic version of "1000+ The Amateur Astronomers' Field Guide to Deep Sky Observing", notes: "10M; 6' diameter; 30-plus faint members with one brighter (8M) member at NNE edge; small and fairly rich."
Houston notes that this open cluster, in southern Gemini, can be seen with large binoculars. The cluster is a little less than 10' in diameter with a total magnitude of 9.7.
Steve Coe, observing with a 13" f/5.6, notes: "Pretty bright, pretty large, much compressed. About 80 stars of a wide variety of mags with a bright yellow star in the middle. It can be seen in the 11X80 finder, this fine cluster has many curved lines of stars at 135X."
Your skills: Advanced (many years); Date/time of observation: 12 Feb 1999; Location of site: Salome, Arizona USA (Lat +34, Elev 3000 ft); Site classification: Rural; Sky darkness: 8 1-10 Scale (10 best); Seeing: 7 1-10 Seeing Scale (10 best); Moon presence: None - moon not in sky; Instrument: 13" f/5.6 Newtonian on Bigfoot German EQ ; Magnification: 100X, 150X, 220X; Filter(s): ; Object(s): NGC 2355; Category: Open cluster.; Class: ; Constellation: GEM; Data: mag 9.7 size 9.0'; Position: RA 07:17 DEC +13:47
Description: In the 11X80 finder this is a tiny fuzzball next to a 7th mag star. In the 13" at 100X it is pretty bright, pretty small, pretty rich and considerably compressed. I counted 26 member stars at this power and there is a fuzzy background of un-resolved stars with averted vision. Moving up to 150X shows 32 stars resolved in this cluster and a much better view. The cluster takes up about half of the field of view. What was a double star on the east side is now resolved into a triple with a delicate 13th mag companion. It would seem that all the members of this cluster are now resolved. There are several yellow and blue members of this nice cluster. Going to 220X does not bring out any more stars.
POSS: 7' SW of br *. m10.5 * on E side embedded. three *s going SW okay. brtr cen * and knots not consp. #2: m10 * reddish, 2'.3 SE of cen *; cen * comps are: AB: 12.5,13; 13"; pa290; and AC: 12.5,13; 16"l pa177.
6cm - just vis w/two *s nr: 8' NNE, 3' E.
15cm - 7' diam w/35-40 *s. cen * m11-12 or so, has two close comps ~10" WNW & S. cen * ~2 mag fntr than m10 * 3' SE. BS, 15 Mar1988, Anderson Mesa.
25cm - fairly br, 8'-10' diam w/35 *s. brtr one on E. elong a bit N-S.
30cm - found from N2304, via 45 Gem and VX Gem. 149x: 8' SSW of m8.5 *; m9.5 * 3' E. 238x: at least 30 *s in 7' diam. elong pa30, this mostly due to string of three *s running off to SSW. brtr m10 * in center w/two knots.
1994-02-14 01:00 Die Boord 11x80 tripod-mounted. Only a faint glow south of an 8th mag star.
1997 October 28, Tue/Wed: Jonkershoek, seeing 3, transparency 3, sky darkness 4, lim.mag. at south pole 6.0 (naked eye), 10.7 (binoculars). 11x80 tripod-mounted. "An irregular puff, south-southeast of a 9th magnitude star. Seems round, but one or maybe two stars near the centre; like a deformed globular cluster."
Observing site: Little Tycho Observatory
[7h 16m 54s, 13° 47m 0s] A small, 2-3', smattering of faint stars, barely visible, 12... There is a bright, 9mv star very close by.
Location:Blesfontein Guest Farm,Sutherland.
Sky Conditions:The most crystal clear sky possible.Dark moon and stars magnitude 6 and fainter are visible with the naked eye.Excellent clean sky,limited star flickering and brilliant objects.
This open clusters stars are arranged in the letter of an S and that this cluster has an irregular appearance as a misty haze where I have counted 32 stars within a fixed diameter.This open cluster consists of 11th magnitude stars while the bright star that illuminates this cluster is 9.7 magnitude.However most of the stars in this cluster are nearly as bright as each other and that the stars are slightly concentrated towards each other.The stars however are orientated in a NNW-SSE position.This open cluster measures 6.2'x2'.Chart No.211,NSOG Vol.1.
The Messier objects
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