The Caldwell Objects

the brightest stars convene; their finds all lie 15'
to 60' away. This strengthens the theory that lowmass
and high-mass stars become segregated in
clusters as time passes. In NGC 3532's case, this
process is estimated to have taken about 40
million years to complete.
To the naked eye NGC 3532 appears as an
intense cloud more than 1½ Moon diameters
across. A 4th-magnitude Cepheid variable (V382
Carinae) lies on the southeastern edge of the
cluster, whose dense, elliptical core of bright suns
curves away from that star to the west like a tiny
comet tail. My naked-eye estimate of the cluster's
apparent magnitude agrees fairly well with the
published value of 3.0, though I find the cluster
0.2 magnitude (20 percent) fainter. (Note that
V382 Carinae isn't included in my estimate of the
cluster's apparent magnitude.) Train a pair of
7x50 binoculars on NGC 3532 and bang!—five
dozen suns come screaming out at you through a
blizzard of background starlight. The core itself
looks like a 30' x 15' pile of shattered glass
scattered to the east and west, as if a crystalline
globe had just fallen victim to a steamroller.
Another yellow star, shining at 6th magnitude,
lies on the northeastern fringe of this glassy core.
At 23x in the 4-inch NGC 3532 is a stunning
agglomeration of stars packed into a diamondshaped
core crisscrossed by thick dark lanes,
giving it the appearance of a diamond brocade
set in black gold. Filigreed arms radi-
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ate in all directions from this core and some take
on macabre forms. Defocus the view slightly and
some equally magnificent dark features
materialize out of the background fog. Most
noticeable (when seen with south up) is a dark
numeral 7 or letter Τ that slices through the
cluster's eastern side; an ink-black well lies
immediately north of it. Due west of the cluster's
elongated core is a double pond of darkness with
a river of shadows pouring off to the south. I
could go on, but I prefer to let your imagination
give form to the cluster's many dark features.
High magnification does little to enhance this
cluster's beauty. Some black voids show up better
at high power, as do the cluster's many doubles
and tiny stellar groupings. But NGC 3532, like
many of the night sky's treasures, is best admired
at low power.
During my lanuary 2000 trip to New
Zealand I spent some time with Ian Cooper, that
country's leading deep-sky wizard. We were
observing what we could with the naked eye and
binoculars. The Large Magellanic Cloud and the
Carina Milky Way had just peeked above a thick
band of clouds. Suddenly Cooper thrust a pair of
11x80 binoculars my way and pointed excitedly
to NGC 3532. "There ya go, Stephen," he said
with his delightful accent. "Take a look at that . . .
it's the Pincushion." I had to laugh. What a grand
and appropriate name! I don't know who first
pinned it to the cluster, but I hope it sticks.
Deep-Sky Companions: The Caldwell Objects