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RA: 18h 09m 57.5s
Dec: −27° 31′ 29″
Ch: MSA:1415, U2:339, SA:22
Type: open cluster
Mag: B=?, V=?
Size: 15′ x 12′
NGC 6556. The problems with this object began with Sir John himself and his summary description published in the GC, then copied faithfully into the NGC. That description makes the object "F, vL, cE, lbM, rr." On the other hand, JH's original notes read "Cl VI. An oval patch comprised within limits of the field, barely resolvable into infinitely minute points, but which, without attention, appears as a great nebula 15' l; 12' br; hardly bM."
Howe saw it the same way 65 years later: "I see nothin in the entire region except thousands of the minutest stars." Dreyer summarized this in the IC2 Notes simply as "No nebulosity (Ho)."
The object is actually part of the complex region of star clouds and obscuring dust clouds near the Galactic Center. JH's position points to an otherwise unremarkable part of the Milky Way, comprised of, as both he and Howe saw, "... thousands of the minutest stars." I've adopted JH's position, and his description above is apt.
Discovered by Sir John Herschel at the Cape of Good Hope with an 18-inch f/13 speculum telescope. He recorded it as "Cluster VI An oval patch comprised within limits of the field, barely resolvable into infinitely minute points, but which, without attention, appears as a great neb 15' long, 12' broad; hardly bM."
The RNGC (Sulentic and Tifft 1973) notes that this is a nonexistent object. Their coded description reads NF S.
The Messier objects
The Bennett objects
The Caldwell list
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