Sky and Telescope - July 2018 - 61
p FUZZY STARBALL AND WEE WISP The second-tier globular cluster M56 (left) is an easy catch in any telescope, but resolving it into individual
stars is more difficult. Look for at least two "arms" extending roughly northwestward from the cluster. This image combines visible and near-infrared
exposures taken with Hubble's Advanced Camera for Surveys, and the field of view is approximately 3.3′ × 3.3′. There's more to the planetary nebula
NGC 6765 than meets the eye (right). In a high-power ocular, it's a tiny, elongated, asymmetrical patch. Images, though, reveal multiple components
that greatly enlarge the object's physical size.
M56: N ASA / ESA; NGC 6765: STEFA N BINNE WIES / JOSEF PÖPSEL / CA PELL A OBSERVATORY
Working at 84×, unﬁltered, I noted
an elongated, weirdly uneven wisp - its
irregular form due to NGC 6765, like
M1-92, being a twin-lobed specimen.
At 147×, the diffuse lozenge measured
approximately 25″ × 10″ and was clearly
asymmetric, the southwest part smaller
and fainter than the northeast part. A
15.8-magnitude star hugged the end of
the luminous northeast portion.
The gap between star and nebula
was obvious at 228×. An O III ﬁlter
Targets off the Beaten Track
Purely for the Fun of It
0.2′ × 0.1′
19 h 11.1m
erased the star but revealed a tenuous
halo around the northeastern half of
NGC 6765. Additional magniﬁcation,
unﬁltered, accentuated the longish,
oddly misshapen outline of this intriguing planetary. My lone disappointment
concerned the 16th-magnitude central
star, which stayed beyond my reach.
Angular sizes and separations are from recent catalogs. Visually, an object's size is often smaller than
the cataloged value and varies according to the aperture and magnification of the viewing instrument.
Right ascension and declination are for equinox 2000.0.
Admittedly, my "off the beaten track"
tour was a one-off, arbitrary exercise. I
saw it as a mini-treasure hunt, and my
pursuit of the loot embodied the kind
of observing project I enjoy most: a
variety of often-overlooked objects in a
relatively small area of sky that can be
explored in an hour or two from a dark
site. Hit the celestial backroads and
sight these eight for yourself.
¢ Contributing Editor KEN HEWITTWHITE has been observing deep-sky objects from alpine sites in southern British
Columbia for the past 45 years.
s k y a n d t e l e s c o p e . c o m * J U LY 2 0 1 8