The Caldwell Objects

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NGC 6541
Type: Globular Cluster
Con: Corona Australis
RA: 18 h 08 m 02.2 s
Dec:-43° 42' 54"
Mag: 6.3
Diam: 15'
Dist: 22,300 light-years
Disc: James Dunlop, listed
in his 1827 catalog
J. HERSCHEL: Globular,
bright, round, extremely
compressed, very fine;
diameter of most compact
part equal to 11 seconds of
time in right ascension; stars
of magnitude 15 to 16.
The scattered stars extend to three times the
diameter and die away very gradually, (h 3726)
CORONA AUSTRALIS, THE SOUTHERN CROWN, is
an attractive laurel of similarly bright suns close
to the waist of Sagittarius, just south of the
Teapot asterism. The constellation adorns the
southern rim of our galaxy's great central bulge,
and though its brightest stars shine at around 4th
magnitude they stand out prominently against
the Milky Way, like distant camp-fires dimmed
by morning mist. Ptolemy called it the Southern
Wreath, perhaps a victor's garland, while
classical poets saw it as the crown that Bacchus
placed in the sky to honor his mother, Semele.
Like its northern counterpart, Corona Borealis,
the stars in the Southern Crown have a symmetry
that mystically lures our gaze to them despite
their modest sheen. Perhaps Ptolemy, who leased
his mind to the world of the occult, saw this
crown as a befit-
GC/NGC: Globular, bright, round, extremely compressed,
gradually brighter in the middle, well resolved, stars of
magnitude 15 to 16.
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ting decoration to honor the heavens for its
victory over human affairs.
To see our next Caldwell target we must
shift our gaze 5° west of the Crown, to SAO
228708, a 5th-magnitude sun halfway between
magnitude-4.6Theta (θ) Coronae Australis and
2nd-magnitude Theta (θ) Scorpii in the Scorpion's
Tail. SAO 228708 also makes a near-equilateral
triangle with Theta Coronae Australis and
magnitude-3.5 Alpha (α) Telescopii to the south.
If you can locate SAO 228708, even in binoculars,
you will have found the equally bright globular
cluster NGC 6541, because it lies less than ½° to
the southeast of that star. Although the cluster's
full extent is 15' (half the size of the full Moon),
its core is greatly condensed and easy to see. In
7x35 binoculars from Hawaii, the globular
appears as a small, tight, and concen-
The Caldwell Objects 311