Sky & Telescope - September 2024 - 43

Deneb
α
γ
ν
Sadr
M29
CYGNUS
ε
Binocular Highlight by Mathew Wedel
Where Secrets Are
Kept
T
R
Vega
LYRA
M57
+20°
his is my 100th column, and to celebrate I'm
going to revisit my all-time favorite target: the
heart asterism at the center of Cygnus, the Swan.
Cygnus is a phenomenal hunting ground for
θ
0°
M11
S ERP ENS
( CAUDA )
UTUM
M16
M17
binocular observers. It has star clusters, bright and
dark nebulae, double stars, and asterisms, all piled
together to achieve a staggering density of spectacle
(see, e.g., S&T: Sept. 2021, p. 34). But the jewel
that keeps drawing me back to Cygnus is Sadr, or
Gamma (γ) Cygni, and its associated asterism. The
word sadr means " chest " or " heart " in Arabic, and
there's a neat linguistic turn in its meaning. Sadr is
the place where secrets are kept: It's the anatomical
chest, but it's also a treasure chest - just like the
human heart.
The star Sadr is located at the center - or heart -
of the celestial Swan, but the story gets stranger still,
for around the star is a 2° ring of stars and star clusters
that bends inward at the northeast to form a heart
shape. The star at the heart of Cygnus is surrounded
by an asterism in the shape of a heart. That asterism
is visible in binoculars but not to the naked eye, so
it is a secret held in the chest of the Swan - or sadr,
where treasures are kept. Those multiple reflections
of meaning, like mirrors facing each other, make my
hair stand on end.
By the time you read these words, I'll be out in
WHEN TO
-40°
9h
g Sou
USE THE MAP
Late July Midnight*
Early Aug 11 p.m.*
Late Aug
10 p.m.*
Early Sept 9 p.m.*
Late Sept Dusk
*Daylight-saving time
the late summer dark with my binoculars, once more
teasing out the secrets of the night sky. One hundred
columns is a good start, but the celestial ocean
stretches inexhaustibly before us. Let's see how much
more is out there.
¢ The Binocular Highlight paradox: The longer
MATT WEDEL writes this column, the less he worries
over finding things to write about.
sk yand te l escope .o r g * SEPTEMBER 2024 43
5
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Sept 7
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