Sky & Telescope - January 2023 - 29

molecular clouds at the heart of the
Celestial Swan. At a distance of 5,000
light-years, this region harbors hundreds
of luminous stellar nurseries.
Unfortunately, we can't see them at
visual wavelengths because they're
hidden behind the dark Cygnus Rift.
The first hint of the Wave comes in
the form of the Snow Angel Nebula
(Sh2-106), about 3,500 light-years
away. It's a challenging object for imagers
and all but out of reach for visual
observers with amateur instruments.
We get our first visual glimpse of
23h
22h
β
7023
CEPHEUS
α
+60°
δ
LAC
Le Gentil 3
+50°
IC 5146
M39
the Wave at the famed North America
Nebula (NGC 7000), just 3° east of
Deneb. In a wide-field scope or binoculars
it presents a pale sheet of light
spanning 120′ × 100′, with dozens of
embedded 9th- and 10th-magnitude
stars. A 3° or larger field of view frames
it nicely. The North America Nebula
and the fainter Pelican Nebula
(IC 5070) next door constitute small sections of an H II region
set aglow by a hot young star, which is obscured from sight by
intervening dust. Both nebulae lie some 2,600 light-years away.
(See page 58 in the September issue for further observing tips.)
In pristine observing conditions, some of the Wave's dark
7000
CYGNUS
+40°
ν
Northern
Coalsack
M29
η
ε
clouds emerge to the unaided eye against the background
Milky Way. The Northern Coalsack, nestled between
Alpha (α) Cygni (Deneb), Gamma (γ) Cygni (Sadr), Nu (ν)
Cygni, and Epsilon (ε) Cygni, spans 7° × 5° and lies at the
near edge of Cygnus X. Another dark nebula, the sprawling
Le Gentil 3, is situated about 7.5° north-northeast of Deneb
and stands out prominently against a brighter and more uniform
stellar background.
The Cocoon Nebula (IC 5146) features a photographically
reddish emission nebula overlapping with a fainter bluewhite
reflection nebula, with the clearly etched dark cloud
Barnard 168 extending about 2° to the west. The luminous
portion of the Cocoon spans around 10′ and has an integrated
magnitude of 7.2. An 85-mm refractor and an Ultra
High Contrast (UHC) filter at 24× tease out its circular glow
under suburban skies, and I can make out two 10th-magnitude
stars within. With 12×36 binoculars I can just spot the
Barnard dark cloud. This three-in-one gem also harbors Collinder
470, a loose and relatively sparse open star cluster.
If you're looking at a star chart of the region, you'll see
that more star clusters abound in northern Cygnus and
neighboring Lacerta, but all of them either lie in front of
or behind the Radcliffe Wave, or they're simply too old and
predate it. Over in Cepheus the sprawling nebula IC 1396 lies
slightly behind the Wave. However, 3.5° southwest of Beta
(β) Cephei, we find the Iris Nebula (NGC 7023), a small
reflection nebula embedded in a larger dark cloud about 1,300
α
Deneb
IC 5070
γ
δ
Expansive Dark Nebulae
Invisible bridges of tenuous gas lie
eastward on the Radcliffe Wave
and thread through Cassiopeia and
Camelopardalis. Coming to Perseus,
though, we find denser clouds and a
pair of visible tracers. Look about 3.3°
west-southwest of Omicron (ο) Persei
(Atik) to spot NGC 1333, a reflection
nebula in a much larger dark cloud.
German astronomer Eduard Schönfeld
discovered it in 1855 with a 3-inch refractor, so it's an
easy object in dark sky. This tiny, 5.7-magnitude oval looks
like a fuzzy star at low magnification in my 10-inch Dobsonian,
but its nebulous form emerges at 92× along with its
central 10th-magnitude star.
Just ¼° southeast of Atik sits IC 348, another tiny cluster
of blue-white stars some 1,000 light-years away just flickering
to life. Its designation refers to the cluster itself and to
μ
η
21h
20h
ε
19h
δ
DRACO
1
2
3
4
5
light-years away. At magnitude 7.2 and
10′ across, the Iris Nebula looks lovely
in a small telescope. I can spot it with
my 85-mm refractor at 24×. It takes
magnification well: At 67× the nebula
displays a complex structure reminiscent
of an irregular spiral galaxy. A
central 7th-magnitude blue-white star
illuminates this small patch of interstellar
dust. An inky-black nebulosity,
about 0.5° across, surrounds the Iris.
TRIPLE DELIGHT The Cocoon Nebula presents three types of nebulae
in one spot in space: emission, reflection, and dark. You'll find it in
a fairly empty bit of sky in the far eastern reaches of Cygnus by slewing
some 12½° slightly north of due east of Deneb.
sk yand tele scope .o r g * JANUARY 2023 29
MASIL IMAGING TEAM
Star magnitudes
Sky & Telescope - January 2023

Table of Contents for the Digital Edition of Sky & Telescope - January 2023
