The Caldwell Objects

100
while performing this feat is a bonus.)
From Hawaii 3rd-magnitude Lambda Centauri (a
type B9II blue giant) is low, achieving an altitude
of only 7° at upper culmination. Lambda
Centauri has the same declination as Alpha (α)
Crucis (Acrux), the southernmost star in the
famous Southern Cross, and it can be found
about 5½° west of it. Fortunately, the 4,200-foot
summit of Kilauea offers a reasonably clear view
of the southern Milky Way. Still, my views pale
in comparison with those from the Southern
Hemisphere, where the Centaurus Milky Way
curdles into fluid folds of starlight high
overhead.
Lambda Centauri is easy to spot, being the
brightest star roughly halfway between Acrux
and the great Eta (η) Carinae Nebula (Caldwell
92). Seen on photographs, Lambda Centauri lies
on the eastern rim of a conspicuous caldera of
darkness that breaches the region's copious
starclouds. To be sure you find Lambda Centauri
in this star-rich region, start at Acrux and hop
two naked-eye stars to the southwest. This will
bring you to Eta Crucis,
which is the easternmost
star in a line of four
equally spaced nakedeye
stars (oriented
southeast to northwest)
ending at Lambda
Centauri.
To the naked eye, a
dusty comet tail of light
½° long flows from
Lambda Centauri to the
southeast. This glow
emanates from an
unresolved chain of a
half dozen or so 7th- to
8th-mag-nitude stars in
Collinder 249. The view
is
much the same in 7x50 binoculars, though the
star chain is well detached from Lambda
Centauri. Under averted vision the chain
transforms into a rectangle of scintillating
starlight surrounded by a slight fog. Knowing
that a nebula (IC 2948) surrounds this region, it is
easy for me to assume that the glow comes from
interstellar gas, but I could not convince myself
of this from my Hawaii site; the glow, I feared,
might also come from unresolved stars. The
emission nebula does pop out dramatically in
many photographs of the region, such as that
shown on page 397. In fact, some photographs
suggest that IC 2948 rivals the nearby
400 Deep-Sky Companions: The Caldwell Objects