Sky and Telescope - November 2017 - 35

red shifts, and this group illustrates the situation well. The
brightest galaxy here, NGC 7320, has a much lower red shift
than its neighbors and based on that finding is considered to
be a foreground object. The other members show evidence of
gravitational interaction and are most likely in the process
of merging. Recent research reveals that one member, NGC
7318B, is falling into the center of the group at an impressively high velocity (about 900 km/s), generating huge shock
waves and bursts of X-rays.
HCG 92 was discovered on September 23, 1876, by
Édouard Stephan using the 80-cm Foucault reflector from
Marseilles, France. He described just four objects, being
unable to resolve the pair of galaxies NGC 7318A and NGC
7318B separately. NGC 7320C was added to the group in the
20th century and has since been shown to be a true member
of the interacting group.
The quintet is located a ½° south-southwest of NGC 7331.
Moderate aperture will rather easily reveal three separate

The November sky contains a large number of Hickson
groups. For this tour, I've selected nine groups with a range
of difficulty that offer most observers a realistic chance at
successful detection. Success here is subjective, however.
You may fi nd it reasonable to deem detection of any part of
the group, even the composite group as just a single object,
as a success. The most demanding observers might accept
nothing short of resolving all of the members into discrete
components, and that will be a high hurdle to leap indeed.
The aperture of your scope and the quality of your sky will,
of course, limit what's possible, but all of the groups discussed here contain one or more members detectable with
as small as an 8-inch telescope.

Pegasus
Stephan's Quintet (HCG 92) in Pegasus is one of the bestknown groups on the list and an excellent place to start.
Hickson sought to study tight groupings with discordant

g

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ANDROMEDA i

M31
M32

+

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Star magnitudes

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`

a

HCG 10

TRIANGULUM

/

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+30°

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o

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HCG 92
(Stephan's
Quintet)

2
3
4
5
6

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PEGASUS

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HCG 93
M74

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PISCES
¡

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HCG 96

b
t

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HCG 7

1h 30m

1h 00m

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23h 30m

23h 00m

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22h 30m

a

s k y a n d t e l e s c o p e . c o m * N O V E M B E R 2 0 17

35



http://www.skyandtelescope.com

Sky and Telescope - November 2017

Table of Contents for the Digital Edition of Sky and Telescope - November 2017

Contents
Sky and Telescope - November 2017 - Cover1
Sky and Telescope - November 2017 - Cover2
Sky and Telescope - November 2017 - 1
Sky and Telescope - November 2017 - Contents
Sky and Telescope - November 2017 - 3
Sky and Telescope - November 2017 - 4
Sky and Telescope - November 2017 - 5
Sky and Telescope - November 2017 - 6
Sky and Telescope - November 2017 - 7
Sky and Telescope - November 2017 - 8
Sky and Telescope - November 2017 - 9
Sky and Telescope - November 2017 - 10
Sky and Telescope - November 2017 - 11
Sky and Telescope - November 2017 - 12
Sky and Telescope - November 2017 - 13
Sky and Telescope - November 2017 - 14
Sky and Telescope - November 2017 - 15
Sky and Telescope - November 2017 - 16
Sky and Telescope - November 2017 - 17
Sky and Telescope - November 2017 - 18
Sky and Telescope - November 2017 - 19
Sky and Telescope - November 2017 - 20
Sky and Telescope - November 2017 - 21
Sky and Telescope - November 2017 - 22
Sky and Telescope - November 2017 - 23
Sky and Telescope - November 2017 - 24
Sky and Telescope - November 2017 - 25
Sky and Telescope - November 2017 - 26
Sky and Telescope - November 2017 - 27
Sky and Telescope - November 2017 - 28
Sky and Telescope - November 2017 - 29
Sky and Telescope - November 2017 - 30
Sky and Telescope - November 2017 - 31
Sky and Telescope - November 2017 - 32
Sky and Telescope - November 2017 - 33
Sky and Telescope - November 2017 - 34
Sky and Telescope - November 2017 - 35
Sky and Telescope - November 2017 - 36
Sky and Telescope - November 2017 - 37
Sky and Telescope - November 2017 - 38
Sky and Telescope - November 2017 - 39
Sky and Telescope - November 2017 - 40
Sky and Telescope - November 2017 - 41
Sky and Telescope - November 2017 - 42
Sky and Telescope - November 2017 - 43
Sky and Telescope - November 2017 - 44
Sky and Telescope - November 2017 - 45
Sky and Telescope - November 2017 - 46
Sky and Telescope - November 2017 - 47
Sky and Telescope - November 2017 - 48
Sky and Telescope - November 2017 - 49
Sky and Telescope - November 2017 - 50
Sky and Telescope - November 2017 - 51
Sky and Telescope - November 2017 - 52
Sky and Telescope - November 2017 - 53
Sky and Telescope - November 2017 - 54
Sky and Telescope - November 2017 - 55
Sky and Telescope - November 2017 - 56
Sky and Telescope - November 2017 - 57
Sky and Telescope - November 2017 - 58
Sky and Telescope - November 2017 - 59
Sky and Telescope - November 2017 - 60
Sky and Telescope - November 2017 - 61
Sky and Telescope - November 2017 - 62
Sky and Telescope - November 2017 - 63
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Sky and Telescope - November 2017 - 65
Sky and Telescope - November 2017 - 66
Sky and Telescope - November 2017 - 67
Sky and Telescope - November 2017 - 68
Sky and Telescope - November 2017 - 69
Sky and Telescope - November 2017 - 70
Sky and Telescope - November 2017 - 71
Sky and Telescope - November 2017 - 72
Sky and Telescope - November 2017 - 73
Sky and Telescope - November 2017 - 74
Sky and Telescope - November 2017 - 75
Sky and Telescope - November 2017 - 76
Sky and Telescope - November 2017 - 77
Sky and Telescope - November 2017 - 78
Sky and Telescope - November 2017 - 79
Sky and Telescope - November 2017 - 80
Sky and Telescope - November 2017 - 81
Sky and Telescope - November 2017 - 82
Sky and Telescope - November 2017 - 83
Sky and Telescope - November 2017 - 84
Sky and Telescope - November 2017 - Cover3
Sky and Telescope - November 2017 - Cover4
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