Sky and Telescope - August 2016 - 55

Sue French

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

at 164× it displays about 15 faint to very faint stars over
a patchy mist of unresolved stars. It's roughly 5′ across
and more concentrated in the center. My 10-inch reﬂector at 166× plucks out 40 stars gathered into an odd shape
covering 6′. A dense clump of stars dominates the center,
with a sparse scattering of stars to its south, as though
some trickled out of the main mass. A starry band reaches
westward from the clump, and from its end, a sweeping

AQUILA

λ
β

α
SCUTUM

The small constellation
Scutum, the Shield, stretches
across the Milky Way to meet
Aquila in the east.

PK CHEN

its core. I've tried to portray M11 as seen through my
130-mm refractor at 164× (facing page), but the dusky
ﬁssures splitting its rafts of stars are best captured with
your own eye. No image or sketch can truly do justice to
this magniﬁcent cluster.
M11 is also the bauble decorating the Bracelet, an
asterism that Arizona amateur Bill Dellinges noticed
with 7×50 binoculars. Dellinges says that the Bracelet is
one of those shapes that, once imagined, you can never
again fail to see. Through my husband's 7×42 binoculars,
it's easy to imagine an open-ended bracelet. It starts at
14 Aquilae and then curves through the stars 15, Lambda
(λ), and 12. The Bracelet then crosses over into Scutum
with Eta (η) Scuti and proceeds through the stars HD
174208 and Beta (β). Finally it returns to Aquila, ending
at the star pair 7 and 8 Aquilae. All but three are magnitude 5.4 or brighter, so stargazers blessed with dark
skies may be able to see most of the asterism with the
unaided eye. When R Scuti is near maximum light, it
adds another star to the bracelet.
A lesser gem on the bracelet is Apriamaswili 1, discovered by S. P. Apriamasvili of the Abastumani Observatory in 1964. The ﬁrst spelling is the object's name
as listed in the Simbad Astronomical Database, and the
second is the author's name as you'll ﬁnd on the discovery paper in the SAO/NASA Astrophysics Data System.
Confusing matters further, some journal papers by the
same astronomer are found under the name Apriamashvili. We owe these diﬀerences to various transliterations
of a name written in Georgian script. The cluster is
often called Basel 1, a later name bestowed in 1970.
Apriamaswili 1 is boxed up in a 35′ × 13′ trapezoid
formed by four bright stars. My 130-mm scope at 48×
shows a little knot of several faint stars and haze, which
at 102× breaks up into 18 faint to very faint stars loosely
tossed across 5′ of sky. Through my 10-inch reﬂector at
68×, the delicate cluster becomes a fairly conspicuous
bunch of at least 20 stars, magnitude 11 and fainter. A
magniﬁcation of 115× makes it clear that the group has
an irregular shape, as well as indeﬁnite borders. Stragglers seem to expand the group to 7′ and 30 stars.
Let's turn our attention to the open cluster NGC
6704, discovered by the outstanding German astronomer and comet-hunter Friedrich August Theodor
Winnecke with his 3-inch Mertz comet seeker in 1854.
Through the small refractor he saw it as a faint nebula,
but when he later viewed it with the 9.6-inch refractor at
the observatory in Berlin, he found that it was a coarse
cluster of stars.
NGC 6704 sits 1.1° north of M11 within a ½° oval of
stars, 8.6 magnitude and fainter. The cluster looks like a
granular haze through the 130-mm refractor at 48×, while

The Jeweled Shield
Object
Messier 11
Bracelet

Type

Mag(v)

Size/Sep

Dec.

Open cluster

5.8

11′

18h 51.1m

-06° 16′

Asterism

4.8° × 2.6°

18h 56.5m

-04° 39′

48.1m

-05° 51′

Apriamaswili 1

Open cluster

8.9

5.5′

18h

NGC 6704

Open cluster

9.2

5.0′

18h 50.8m

-05° 12′

Trumpler 35

Open cluster

9.2

6.0′

18h 43.0m

-04° 14′

Star cloud

47′

18h 39.6m

-04° 46′

33.4m

-04° 58′
-12° 28′

NGC 6682
Sharpless 2-61
UY Scuti

Emission nebula

2.0′

18h

Red supergiant

8.6-10.5

18h 27.6m

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.

Sk yandTelescope.com August 2016

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Sky and Telescope - August 2016

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