Sky & Telescope - December 2018 - 56

DECEMBER 2018 OBSERVING
Deep-Sky Wonders
t If you want to conquer the Muscle Man,
pick up a pair of binoculars. Stock 2 covers
a sprawling 60 arcminutes, so use the widest
field of view to help you win the challenge.

reddish-orange, 8.6-magnitude companion 57″ to the north-northwest.
Our ﬁnal stop is the open cluster
Stock 2, reclining on the CassiopeiaPerseus border, 4° east-southeast of
NGC 663. Only 990 light-years away
from us, Stock 2 is much closer than
our quartet. It's also considerably older
at 170 million years.

Deep-Sky Sights in Cassiopeia
Object
α Cas
M103
Σ131

Type
Double star

Mag(v)
2.2, 8.8

Open cluster
Double star

7.4
7.3, 9.9

Size/Sep

Dec.

70″

40.5m

+56° 32′

6.0′

33.4m

+60° 40′

13.9″

33.2m

+60° 41′

46.3m

+61° 13′

NGC 663

Open cluster

7.1

15′

NGC 654

Open cluster

6.5

6.0′

1h 44.0m

+61° 53′

NGC 659

Open cluster

7.9

6.0′

1h 44.4m

+60° 40′

7.7″

46.6m

+61° 16′

57″

21.1m

+64° 39′

60′

14.7m

+59° 29′

Σ153
35 Cas
Stock 2

Double star
Double star

9.4, 10.4
6.3, 8.6

Open cluster

4.4

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.

DECE MBE R 2 018 * SK Y & TELESCOPE

¢ On a cold winter's night, you'll find
Contributing Editor SUE FRENCH keeping warm near her telescopes.

DA N CROWSON

659. They also dwell in the same region
of space, roughly 6,000 to 7,000 lightyears away from us.
Another fetching optical double star
sits north of Delta in the guise of 35
Cassiopeiae. Through my 130-mm
scope at 23×, this nicely contrasting pair shows a pale-yellow-white,
6.3-magnitude primary guarding a

Covering a full degree of sky, Stock
2 is best appreciated through a telescope offering a large ﬁeld of view. Seen
through a wide-angle eyepiece that gives
the 130-mm refractor a true ﬁeld of 2.7°
and a magniﬁcation of 23×, the cluster
boasts 75 stars and is framed by a generous halo of background sky that helps it
stand out from its surroundings. A striking pair of 7th-magnitude, yellow-white
and yellow-orange stars watches over the
cluster from the northeast.
Stock 2 encompasses the head, arms,
and torso of an asterism known as the
Muscle Man, which sprang from the
inventive imagination of Massachusetts
amateur John Davis. The Muscle Man
can be discerned through the 130-mm
refractor, but the scope shows so many
stars that the Muscle Man is nearly lost
in a cloud of tiny midges. Following
the unkindly stereotype of a guy that's
all brawn and no brains, our Muscle
Man has a tiny pin-head, which you'll
see on the cluster's western side. The
Muscle Man's arms are curved up and
in toward his head as though ﬂexing his
muscles. The star marking his northern
hand is yellow, and the southern hand
burns yellow-orange. The Muscle Man's
extended legs stick mostly outside the
cluster, toward the east. His southern
foot glows orange, and the next star
up that leg shines yellow-orange. Four
stars near the end of his northern leg
cast light in shades of yellow-orange to
red-orange.
The Muscle Man is more clearly
perceived through binoculars, which
highlight the brighter stars of the asterism by subduing the many dim stars
of Stock 2. Our strongman clasps a
bright leash of stars that leads us to the
beautiful Double Cluster in Perseus, a
great stop on any night and one of the
featured sights in next month's column.
See you then!

Sky & Telescope - December 2018

Table of Contents for the Digital Edition of Sky & Telescope - December 2018