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NGC 6840 (15,930 of 18,816)


oc gc pln bn dn gx gxcl ast aka lost




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NGC 6840

NGC 6840, VIII 19, h 2058, GC 4522

RA: 19h 55m 18s
Dec: +12° 07′ 36″

Con: Aquila
Ch: MSA:1243, U2:207, SA:16


(reference key)

Type: open cluster

Mag: B=?, V=10

Size: 6′
PA: ?

History and Accurate Positions for the NGC/IC Objects (Corwin 2004)

NGC 6840 and NGC 6843 are two sparce clusters found by JH. N6840 has two groups of seven stars (separated by about 5 arcmin) in its core, surrounded by about 5-6 others. The stars are of fairly equal brightness, all being around 11th to 12th magnitude, and cover an area of 10 arcmin by 8 arcmin. N6843 is poorer with only around a dozen stars, again 11th to 12th magnitude, scattered over a smaller area.

Both are superposed on rich Milky Way backgrounds, so I'm not surprised that they did not stand out enough to be identified for RNGC. In fact, neither may be a real cluster, but proper motions and photometry could tell us that.

Historical observations

William Herschel (c.1784)

Synonyms: H VIII-019

Discovered in 1784 by William Herschel with an 18.7-inch f/13 speculum telescope. He called it "a cluster of coarsely scattered large stars, not rich."

Published comments

Sulentic & Tifft (1973)

The RNGC (Sulentic and Tifft 1973) notes that this is a nonexistent object. Their coded description reads NOCL S.

Contemporary observations

Magda Streicher

2010 June 7

Location: Polokwane

16-inch f/10 SCT (127x 290x)

[19h55m06, +12o14'05"]

Only with a low power eyepiece could I make out a grouping if we can call it one. It appears as a few magnitude 11-13 stars in a very elongated shape from north-east to south-west in a relatively straight line that is somewhat outstanding.

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