Sky and Telescope - November 2016 - 55

Sue French welcomes your comments at scfrench@nycap.rr.com.

Sue French
Left: In small telescopes, planetary nebula IC 5217 will appear stellar,
but a slight cyan or blue color will reveal its true nature. At 120× in
Jaakko Saloranta's 8-inch Dobsonian, it appeared non-stellar, but without detail. Use more aperture and power to tease out its structure.
Below: You'll need a large scope to get more than a hazy blue elongation from IC 5217. On a night of good seeing, Uwe Glahn spotted the
central star and a slightly expanded glow of nebulosity with his 27-inch
f/4.2 reﬂector at 837× to 1172×.

IC 5217

like objects I see are actually foreground stars or tiny
knots of stars. A paper by Kenneth A. Janes and Sadia
Hoq (Astronomical Journal, 2011) gives a color-magnitude
diagram of King 9, which includes 497 stars within a 1½′
diameter that have a photometric membership probability of more than 50%. Of the brightest stars, there's only
one 12th-magnitude, two 14th-magnitude, two 15th-magnitude, and a dozen 16th-magnitude. The authors place
King 9 and NGC 7245 at distances of 24,000 and 11,000
light-years, respectively, so although they appear close
together on the sky, they are separated by a considerable
distance along our line of sight.
Dropping 1.7°° south-southwest from NGC 7245 takes
us to star-spangled IC 1434. Viewed through my 130mm scope at 23×, this open cluster is easy to spot as a
small, granular haze. At 164×, about 30 to 35 stars, most
faint to extremely faint, sparkle within a 7′ group. Four
eye-catching stars zigzag across the southern conﬁnes of
the cluster. The 10-inch scope at 43× reveals a few faint
stars caught in a misty glow overlaid by a southwardﬂying kite of four brighter stars. IC 1434 is delightful at
115×, boasting a multitude of faint suns. Several long
rays of stars sprout from the cluster and make its borders
rather vague.
IC 1434's starﬁeld is heavily contaminated by the
background Milky Way. Its status has been called into
question, but recent sources favor its classiﬁcation as
an open cluster. A study by Eduardo Bica and Charles
Bonatto (Astronomy & Astrophysics, 2011) gives a distance
of 8,500 light-years, plus or minus 2,000 light-years, for
the cluster, while another by Nina V. Kharchenko and
colleagues (Astronomy & Astrophysics, 2013) oﬀers 10,500
light-years.

Next we come to the petite planetary nebula IC 5217,
which dangles 1.3° south of Beta. It makes a squat
isosceles triangle with a 7.4-magnitude star 14′ to the
north-northwest and a deep-orange, 6.5-magnitude star
20′ to the north-northeast. IC 5217 looks starlike in my
130-mm refractor at low power, but its distinctly blue
color gives away its true nature. At 102× the nebula no
longer appears stellar, yet it's still very tiny, while 164×
better shows its diminutive disk. A narrowband or O III
ﬁlter increases its contrast against the background stars.
The O III ﬁlter makes the nebula appear brighter than
any of the nearby stars, which is useful for identifying
IC 5217 if your seeing (image steadiness) blurs the stars
into little pseudo-nebulae. Through my 10-inch reﬂector at 299×, IC 5217 acquires some charm, enticingly
exposing interior detail in the form of a more luminous
north-south region that's brightest in the middle. At a
visual magnitude of about 15.5 and vying with the light
of its nebula, this planetary's central star is game only
for deep-sky hunters with very large telescopes.
The open cluster NGC 7296 is just a short hop 41′
eastward from Beta. My 130-mm scope at 37× unveils
a pretty little spray of ﬁne stars fanning east-southeast
from an orange, 9.7-magnitude star. At 102× I count 15
stars, most arrayed in chains diverging from the bright
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Sky and Telescope - November 2016

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