The Caldwell Objects

galaxy's disk and halo.
NGC 2477 appears finely resolved under close
inspection through the 4-inch at 23x. One linear
ridge of stars runs from northeast to southwest,
with several spidery arms branching off of it to
the southeast and northwest. Each arm is
separated from its neighbors by a dark lane.
Averted vision reveals ribs of starlight, like an Xray
of a human torso with a spine and a rib cage.
Even at 72x the cluster looks magnificent, like
brass knuckles studded with diamonds. Some
streams form looplike strands. Especially
noticeable are a dark hole in the cluster's
northeastern quadrant, a dark ellipse on its
northwestern side, and a narrow pool of
blackness to the southeast. Let your imagination
fly at this power. I saw all sorts of fun sights, like
a spider's exoskeleton and an aerial view of
eroded valleys among hills of starlight. It also
looked as if the ebb and flow of dark waters had
carved away the southern half of the cluster,
leaving in their wake ripples in the stellar sands.
At high power the cluster loses many of its
star chains. But the longer I look, the more
patterns I see. Near the cluster's core are two
stellar concentrations immersed in stellar
haziness — the telltale sign of numerous unseen
cluster members. Use averted vision
The Caldwell Objects
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and see if you can't make out a tiny "keyhole," a
splotch of darkness guarded by three dim stars in
the cluster's core. Now relax your gaze and
wiggle your telescope tube. Many dark patches
and streaks should vibrate into view.
Before leaving this wonderful sight, don't
forget to check out NGC 2451 — number 16 in the
aforementioned list of spectacular non-Messier
objects. This bright open cluster spans a little
more than 1½ Moon diameters, and at least 30 of
its colorful stars are visible in 7x35 binoculars.
These stars seem to burn in adoration of the
cluster's brightest member, c Puppis, which
shines at magnitude 3.6. I see NGC 2451 as a
scorpion approaching me nearly head-on, with
two outstretched claws and an upright tail ready
to sting. It's fitting that this stinging scorpion
travels the sky with NGC 2477, because M71 in
the celestial Arrow sets just as NGC 2477 and
NGC 2451 are rising. Now we can create our own
myth. Ages ago Sagittarius shot Sagitta, the
Arrow, toward Puppis, killing our tiny arachnid.
Feeling sorry for the innocent creature, Zeus
placed the cluster in the company of NGC 2477,
as far as possible from the Arrow in the night sky.
Thus the Arrow will never again slay the stinging
scorpion cluster — just as big brother Scorpius
will never again sting the mighty Hunter, Orion.
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