SkyandTelescope.com July 2014 61Two degrees southwest, in the center of the bowl, I noted
“opacity 6/6, only 13 mostly faint stars in the entire low
power fi eld.” The only comparably star-poor area that I
have seen within the entire Milky Way is the one that
runs eastward from the fi ne binocular trio Rho Ophiu-
chi, 3°° north of Antares.
The ½°-long Snake Nebula, Barnard 72, resembles a
wisp of smoke wafting from the bowl of the much larger
Pipe on wide-fi eld images. Ernst Johannes Hartung’s
classic guidebook, Astronomical Objects for Southern
Tel escopes, considers B72 to be fairly challenging even
from the Southern Hemisphere. Yet superb transparency
behind a cold front at the 1996 Mount Kobau Star Party,
which is held near Osoyoos, British Columbia, allowed
my 16-inch Dob to reveal the entire Snake Nebula. The
easier southeastern loop of the S has opacity 6/6, but the
middle of the northwestern loop is ill-defi ned visually.
Expert observer Chris Beckett saw parts of B72 with
his 125-mm f/6 apochromatic refractor at 53× from Grass-
lands National Park on the Saskatchewan-Montana border
on a memorable night when the limiting visual magni-
tude was 7.2. He writes: “Having failed to observe it on
two previous excellent nights, I fi nally made the observa-
tion on the 29th of July 2011. B72 was seen as a U followed
by a comma, not a continuous S shape. The trick for me
was using the reprinted Barnard & Dobek A Photographic
Atlas of Selected Regions of the Milky Way.”On a night of excellent transparency in northern New
Mexico, I aimed Chaco Observatory’s 25-inch Dobsonian
at B72. At 113× I went after the four adjacent small dark
nebulae immediately south of the Snake. They had been
on my observing list as the Snake’s Eggs for years, and I
decided to attempt them while I was in the high des-
ert. The small oval vacancy B68, opacity 6/6, was black
and obvious — more so than the Snake itself. An 11th-
magnitude star lies just outside the dark nebula’s western
edge. Adjacent B69 appeared subtle but defi nite. I fi nally
detected B71, but this one was tough — a tiny pore, just
a fraction of B69’s size. B70, elongated north-northeast to
south-southwest, was the second-easiest of the Eggs — I
swept it up without a detailed star-hop. B70’s southern
end is darker and more obvious than the northern. The
glaring 6.7-magnitude star that lies between the Snake
and B70 doesn’t help when hunting the Snake’s Eggs!
If you don’t succeed with the Snake, be sure to give
B68 a try before leaving the fi eld. Here at latitude 49°
north, on a night when I had failed on both the Snake and
the rest of its Eggs, my 8-inch Dob working at 51× man-
aged to barely show B68. It appeared about the same size
as in the photograph above. ✦Alan Whitman thanks Australian Tony Buckley for making
large telescopes available to scores of Northern Hemisphere
amateurs so they can explore the wondrous Southern skies.Barnard 72, the Snake Nebula, and its eggs (B68, B69, B71,
and B70) show up particularly well in the red plate of the
fi rst Palomar Sky Survey.
POSS-I / CALTECH / PALOMAR OBSERVATORY
44 OphB74B70B71B69B68B72