T
he autumn sky can be faulted for
having many dim constellations. But
something that always pleases me about
it is the number of fascinating faint
asterisms and even patches of naked-eye
glow that enliven its dark expanse.
Some of these sights are well known,
even famous. I’ll be discussing them in
this column. But I’m also mentioning
two that I discovered for myself and
that don’t seem to be mentioned by
anybody else.
Autumn’s famous asterisms.
When a section of the heavens isn’t
rich enough with many stars to make
showcases of entire constellations, or is
missing a few individual brilliant stars,
we have to resort to compact aster-
isms to fi nd our way around and enjoy
ourselves. Much of autumn’s realm ofAn Assortment of Asterisms
Sometimes overlooked, asterisms pepper the autumn night sky. See which ones you can spot.
the heavens needs these delicate star
patterns — and has them.
Of course, the Great Square of
Pegasus is not a small asterism, being a
bit too big to hide with your fi st held at
arm’s length. But near the Great Square
are two small asterisms that help orga-
nize, and draw our eyes to, two of the
dimmest zodiac constellations.
Directly under the Great Square and
just above the celestial equator shines
the Circlet, marking the head of the
western fi sh of Pisces. The Circlet is like
a dim lasso fl ung in an attempt to catch
the very red star TX Piscium, or the ver-
nal equinox point in the heavens. Not
far west of the Circlet and notably right
on the celestial equator is the Y-shaped
Water Jar or Urn of Aquarius (used by
Aquarius the Water Carrier to pour out
his water). This little
pattern aids in fi nding
the impressive globu-
lar star cluster M2,
directly west of the
Water Jar and Alpha
Aquarii.
Autumn’s famous
glows. How wonder-
ful it is, far from city
lights, to look with
the naked eye and see
the different extended
glows of autumn’s
celestial objects —
and to know that
several of them are
very important in the
hierarchy of the local
universe.
One, of course,
is M31, the Great
Galaxy in Andromeda,
the Milky Way’s big
sister with which it
will collide in 4 billion
years or so. One featof the great Walter Scott Houston I’ve
been able to replicate is to trace M31’s
soft blur, its elongated smear of light,
out to over 5° in length — in a sky dark
enough to reveal to the naked eye the
elusive glow of M33, the lesser local
galaxy in Triangulum.
Between the little pattern of Tri-
angulum and Almach (the wonderful
double star Gamma Andromedae), the
naked eye ca n see the glow of the large
open cluster NGC 752, which is itself
adjacent to the binocular asterism the
Golf Putter. NGC 752 in fact serves as
the stellar golf ball at the end of the
club. Almost directly between Almach
and Perseus’s Algol is another naked-eye
glow, that of the open cluster M34. But
of course the most prominent cluster of
autumn that looks to the naked eye like
a glow — an elongated, two-lobed glow
— is the Double Cluster of Perseus.
The Arc of the King and 1 Cas
Patch. A few years ago, while watch-
ing the Perseid meteor shower, I fi rst
hit upon a new asterism visible to the
naked eye in rather dark and clear
skies. This is a perfect curve of faint but
equally spaced stars extending all the
way from Gamma (γ) Cephei (Errai)
to Beta (β) Cephei (Alfi rk). The other
component stars are Pi Cephei, 31
Cephei, 24 Cephei, and 11 Cephei. I fi nd
this asterism’s visibility a good measure
of sky conditions and for now we could
call it the Arc of the King.
I’m going to set as a goal for any
interested readers an area of star-
specked glow that I fi rst noticed two
summers ago. I call it 1 Cas Patch. Find
the magnitude-4.8 star 1 Cassiopeiae
and tell me what you see there with the
naked eye. I’ll have more to say about it
in an upcoming column.¢FRED SCHAAF welcomes your letters
and comments at [email protected].Under the Stars by Fred Schaafskyandtelescope.com • NOVEMBER 2019 45αθγβπ312411ιδ
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