The Caldwell Objects

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NGC 6025
Type: Open Cluster
Con: Triangulum Australe
RA: 16 h 03.3 m
Dec: -60° 25'
Mag: 5.1; 5.5 (O'Meara)
Diam: 15'
Dist: 2,500 light-years
Disc: Abbé Nicolas Louis de
Lacaille, included in his 1755 catalog
J. HERSCHEL: Large, brilliant cluster
VII class; fills field, not rich, stars 8,
9,10,11th mag[nitude], with smaller
[fainter]. Chief star 8th mag [nitude]
taken, in the southern part of cluster,
(h 3616)
GC/NGC: Cluster, bright, very large,
pretty rich, little compressed, stars
of 7th magnitude and fainter.
ALPHA (α) AND BETA (β) CENTAURI POINT
almost directly to our next Caldwell object, the
5th-magnitude open cluster NGC 6025 in the
south circumpolar constellation Triangulum
Australe. The cluster literally kisses the border of
Norma and is only about 3° southwest of NGC
6087 (Caldwell 89). To find NGC 6025, just point
your binoculars 10° (the width of a fist held at
arm's length) due east of Alpha Centauri and
look for a bright but fuzzy string of starlight.
Better yet, hop 3° north-northeast of magnitude-
2.8 Beta Trianguli Australis.
The Southern Triangle is a fine constellation.
It first appeared in Johann Bayer's 1603
95
Uranometria, but Richard Hinckley Allen notes
that Pieter Theodor had formed it nearly a
century earlier. Unlike the sky's dim northern
Triangle, Triangulum Australe is obvious, as it
comprises three stars of near-equal brightness:
the "three patriarchs" (probably Abraham, Isaac,
and Jacob) of Jansenius Caesius, a 17th-century
Dutch globe maker. Beta Trianguli Australis
marks the Southern Triangle's northern tip. Years
ago, astronomers believed that the star was 10
parsecs (32.6 light-years) distant — precisely the
distance at which a star's apparent magnitude
equals its absolute magnitude. This made the star
a standard for deter-
The Caldwell Objects 381