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NGC 6266
Messier 62, ESO453-SC014
RA 17:01:12
Dec -30°07.0'
Globular
cluster |
Discovered by Messier in June 1771. He
re-observed it in 1779, describing it as “a very fine nebula; it resembles
a little comet.. It is bright in the centre and is surrounded by a faint glow...”
In the Philosophical Transactions, 1814,
William Herschel wrote “extremely bright, round, very gradually brighter in
the middle, easily resolvable, about 4' in diameter. With 240 power and strong
attention I see the stars of it. It is a miniature of the 3d of the Connoissance
des Temps.” In the Philosophical Transactions, 1818, William Herschel
wrote: “1783, 10 feet telescope. With 250 power, a strong suspicion,
amounting almost to a certainty, of its consisting of stars. 1785, 1786, 20 feet
telescope. Extremely bright, round, very gradually brighter in the middle, about
4 or 5' in diameter; 240 power with strong attention showed the stars of it. The
cluster is a miniature of the 3d of the Connoissance.”
Dunlop 627 “160 Scorpii is a pretty
bright round nebula, considerably condensed, and rather suddently bright at the
centre, pretty well defined at the margin.”
h: “globular, B, L, R, gmbM, but not to a
nucleus; stars 15th mag, v fine, diam in RA = 13 seconds.” On a second
occassion he called it “globular, superb, vB, R, psvmbM, about 7' diameter,
all resolved into stars 15th mag, very equal.” His third observation was
recorded as “globular, vB, L, R, pgvmbM, perfectly resolved with left eye,
hardly with right. the most condensed part is a perfect blaze, but not quite in
the centre. The southern part runs out further. A beautiful object (See figure
13, Plate VI) Diam = 13.5 seconds in RA.” It was next recorded as “globular,
vB, L, R, gvmbM, to a blaze; dima in RA = 27 seconds, stars 14..16th mag,
superb.” The final record reads: “B, L, R or lE, towards the N.f.
side, where there is even some feeble appearance of another centre of
condensation; psbM, almost to a nipple, stars 15th mag.”
Burnham notes that: “The identification
of M62 as a star cluster was first made by William Herschel; he thought it a
miniature of the cluster M3 in Canes Venatici. Admiral Smythe saw here “A
fine large resolvable nebula; an aggregated mass of small stars running up to a
blaze in the centre.” The thickest massing of stars, according to J.E.
Gore, is a “perfect blaze, but not quite in the centre.” The cluster
is seen against, and is probably embedded in, a rich Milky Way star field, so
that the area, for many degrees around the group, is sprinkled with multitudes
of tiny star-sparks....M62 is one of the most unsymmetrical clusters; the
non-spherical outline was probably first noticed by Sir John Herschel in 1847,
and remarked upon by Bailey in 1915. Shapley called it “the most irregular
globular cluster” and from star counts determined that the major axis is
oriented toward PA 75 . The lack of symmetry was found to be “marked not
only in the distribution of stars but especially in the distribution of
variables, 19 being found north of the centre and 7 to the south...” Hogg
gives the total diameter as 6.3', total integrated photographic magnitude as
8.16 and the average magnitude of the 25 brightest stars as 15.9. A study by W.
W. Morgan of Yerkes Observatory indicates this globular cluster to have a
spectral type of F8.
Houston recalls observing this cluster from
Mexico: “About as bright and large as NGC 6333, M9, it was easily found in
a surprisingly uniform field of star dust.. Houston notes that NGC 6273, M19,
some four degrees away, is perhaps a magnitude fainter.
Tom Lorenzin: “6.5M; 9' diameter; soft
glow with brighter center; uneven outline with brightest part of center not
centered; brighter stars well resolved over diffuse background glow.”
Donald J. Ware:”A fine, bright globular
cluster with resolution at the edges, and a bright core. About 10' in diameter,
this cluster's core is slightly offset to the southeast. Stars seem to fan out
to the west, giving this globular rather unique appearance.”
11x80: (strong moonlight):
Appears very similar to M19: both these globulars can just be seen in the same
field. It appears to have the same size and magnitude of M19, but M62 is
slightly more visible and easily seen. Look close by due north for a very nice,
reasonably close pair of stars. This cluster can be found quite reasily via a
trail or chain of stars starting from Epsilon Sco. (exurban skies): Small,
fierce round spot. Much much smaller than shown on the Uranometria map.
(suburban skies) [AS] |
