60 July 2014 sky & telescopeAlan Whitman
Going DeepThe Snake and Its Eggs
Southernmost Ophiuchus contains some of the sky’s best dark nebulae.
when I got my fi rst naked-eye view
of the 7°°-long Pipe Nebula (LDN 1773) at the 1983 Texas
Star Party. This nebula is in southern Ophiuchus, around
declination –25°, so it’s never far above the horizon in my
native Canada. But the Pipe was clearly etched against
the bright Milky Way background high in the clear, dark
skies of West Texas.
The next year I was surprised to see the Pipe Nebula
from latitude 50° north on some dark acreage in the moun-
tains of southern British Columbia. The view pleased me
so much that we soon purchased the land as an astronomy-
suitable home site. These days I use the Pipe’s naked-eye
visibility as a test for good summer skies — I don’t attempt
to view diffi cult deep-sky objects unless I can see it.
The Pipe lies midway between Antares and the lid of
the Sagittarius Teapot, just below an arc of four stars —
the only obvious ones in that part of the sky. The bright-
est, 3.3-magnitude Theta (θ) Ophiuchi, is in the center of
the arc. At the southwestern end of the arc, right on the
pipe-stem’s northern edge, lies the constellation’s fi nest
double star: 36 Ophiuchi. It’s a pair of essentially identi-
cal stars that appear deep yellow to my eyes, though mosti was thrilled guidebooks call them orange. The binary is very close to
Earth, just 19.5 light-years distant, and its 5′′ separation
makes it suitable for small scopes.
On a trip home to Canada’s Atlantic coast, I viewed the
Pipe Nebula from my sister’s pasture overlooking the Bay
of Fundy. From this thinly populated area, my 7×50 bin-
oculars revealed the individual but connected dust clouds
that the unaided eye strings together to make the pipe
stem. The huge Prancing Horse Dark Nebula was also
easily visible to the unaided eye — the Pipe Nebula forms
the Dark Horse’s rear legs and hindquarters.
One March morning at Organ Pipe Cactus National
Monument in southern Arizona, the Horse pranced
high in the south-southeast, and with naked-eye averted
vision I could discern the challenging dark lane that runs
from the horse’s foreleg (Barnard 63) to just northeast of
Antares. This lane includes B51/B47 and 5½°-long B44.
While observing the globular cluster NGC 6401 in
Australia from the darker and drier side of the Blue
Mountains with Tony Buckley’s 14.5-inch Dobsonian,
I noted that the sharp border of the Pipe Nebula’s bowl
(B78) was well within the same 81× fi eld as the globular.χχο
θρρξ ωψ36434445455158αο
στ27SCORPIUSSGR(c)(c)RRRRBFAHV449
BMXButterfly
Cluster
M6Galactic CenterAntaresd6416 63836425645164516144623562356284628762876293630463166325634263566355640164406440IC 4592
IC 4601Sh2-9IC 4604
IC 4603vdB 107Sh2-13Sh2-16B41/43B46LDN 1682LDN 1682B57B244
B256B61B61B252B64LDN 1710LDN 219LDN 219 B259B84B84B83aB83a IC 46346369636964456445M4M9M19M19M62M80250°260°Pipe Nebula
LDN 1773B268
B63
B44B45B262 B67aSnake NebulaECLIPTIC–20°
–30°
The chart at left is an excerpt from page 56 of Sky & Telescope’s Pocket Sky Atlas. It shows almost exactly the same section of sky as the photograph at
right; see how many of the dark nebulae you can match up. The Dark Horse (sitting on its haunches, also known as the Pipe Nebula) occupies much of the
left side of the photo. Antares, M4, and the colorful Rho Ophiuchi Nebula are on the right.JIM WINDLINGER