Sky & Telescope - June 2020 - 45

Under the Stars by Fred Schaaf

Ophiuchus and Friends
The celestial serpent bearer has plenty of interesting company.

PUBLIC DOMAIN / WIKIMEDIA COMMONS

I

t seems to me that Ophiuchus often
gets a low rating from beginners for its
supposed lack of observational thrills.
It's true that the star pattern of the Serpent Bearer is big but rangy, with a large
center that has no bright stars. And
though the constellation's globular clusters are amazingly numerous, they're
smaller and dimmer than the mighty
globular blazes in neighboring Serpens,
Hercules, Scorpius, and Sagittarius.
Perhaps it's true that Ophiuchus
doesn't offer the brightest splashy
wonders for small telescopes and novice
observers, but the incredible variety
of its attractions can help improve a
beginner's observing skills and lead to
a greater awareness of the diversity of
deep-sky objects in the heavens.
Diversity? Next month we'll explore
the constellation's collection of globulars, its two huge open clusters, its
many fine double and multiple stars, its
surprisingly prominent dark nebulae,
and its pair of superb planetary nebulae. We'll also meet the second-closest
star in the night sky.
But this month, let's meet Ophiuchus
in the context of its remarkable connections to its constellation neighbors.
Ophiuchus and Serpens. Ophiuchus is a large, human figure pictured
holding a snake: Serpens the Serpent.
Of the 88 official constellations, Serpens is the only one separated into two
parts by another constellation. To the
west of Ophiuchus is the front part of
the snake, known as Serpens Caput (the
Serpent's Head), and to its east is Serpens Cauda (the Serpent's Tail). Combined, Ophiuchus and Serpens stretch
all the way from Boötes to Aquila,
with Ophiuchus's brightest star, 2ndmagnitude Rasalhague, slightly below a
long, long line connecting Arcturus and
Altair. If we counted the areas occupied
by Ophiuchus and Serpens together as

a single constellation, it would be by far
the largest in the heavens.
This arrangement of Ophiuchus
dividing Serpens in two is not just
unique, it's visually striking. The
interesting lights that go before and
after Ophiuchus are Unukalhai (Alpha
Serpentis) in Serpens Caput, and Alya
(Theta Serpentis) in Serpens Cauda.
Unukalhai is a magnitude-2.6 orange
star and is a rough guide to the vicinity
of M5, one of the grand globular clusters
and a favorite of many observers. The
5.8-magnitude cluster is situated about
8° southwest of Unukalhai and just 20′
northwest of the golden, 5.1-magnitude star 5 Serpentis. And what about
Alya? It's a beautiful, easy double star
comprised of magnitude-4.6 and -4.9
components (both white, A5-type stars)
a generous 22.3″ apart. Alya is also the
very end of the Serpent's tail - a line of

stars jutting into the dark Great Rift of
the summer Milky Way.
Ophiuchus and Hercules. The
Alpha stars of Ophiuchus and Hercules are Rasalhague and Rasalgethi,
respectively. They're only 6° apart and
mark the heads of the two big figures.
Hercules is the most famous legendary
strongman, while Ophiuchus is usually
associated with Aesculapius, the god
of medicine, whose snake-entwined
staff remains a symbol of the medical profession today. Which constellation is bigger? The main pattern of
Ophiuchus appears much larger, but
Hercules includes an expansive region
of dim naked-eye stars and occupies a
significantly greater area. Even though
Ophiuchus is the 11th-biggest constellation, Hercules ranks 5th.
Ophiuchus and Scorpius. The
modern boundaries of the constellations have the Sun spending only one
week in Scorpius but almost three weeks
in Ophiuchus. Because of this, some
have started calling Ophiuchus the 13th
constellation of the zodiac.
¢ FRED SCHAAF welcomes your letters
and comments at fschaaf@aol.com.

p SERPENT TAMER This fanciful chart from Alexander Jamieson's 1822 Celestial Atlas portrays
the constellations Ophiuchus and Serpens.
sk yandtelescope.org * JUNE 2 02 0

45


http://www.skyandtelescope.org

Sky & Telescope - June 2020

Table of Contents for the Digital Edition of Sky & Telescope - June 2020

Contents
Sky & Telescope - June 2020 - Cover1
Sky & Telescope - June 2020 - Cover2
Sky & Telescope - June 2020 - 1
Sky & Telescope - June 2020 - Contents
Sky & Telescope - June 2020 - 3
Sky & Telescope - June 2020 - 4
Sky & Telescope - June 2020 - 5
Sky & Telescope - June 2020 - 6
Sky & Telescope - June 2020 - 7
Sky & Telescope - June 2020 - 8
Sky & Telescope - June 2020 - 9
Sky & Telescope - June 2020 - 10
Sky & Telescope - June 2020 - 11
Sky & Telescope - June 2020 - 12
Sky & Telescope - June 2020 - 13
Sky & Telescope - June 2020 - 14
Sky & Telescope - June 2020 - 15
Sky & Telescope - June 2020 - 16
Sky & Telescope - June 2020 - 17
Sky & Telescope - June 2020 - 18
Sky & Telescope - June 2020 - 19
Sky & Telescope - June 2020 - 20
Sky & Telescope - June 2020 - 21
Sky & Telescope - June 2020 - 22
Sky & Telescope - June 2020 - 23
Sky & Telescope - June 2020 - 24
Sky & Telescope - June 2020 - 25
Sky & Telescope - June 2020 - 26
Sky & Telescope - June 2020 - 27
Sky & Telescope - June 2020 - 28
Sky & Telescope - June 2020 - 29
Sky & Telescope - June 2020 - 30
Sky & Telescope - June 2020 - 31
Sky & Telescope - June 2020 - 32
Sky & Telescope - June 2020 - 33
Sky & Telescope - June 2020 - 34
Sky & Telescope - June 2020 - 35
Sky & Telescope - June 2020 - 36
Sky & Telescope - June 2020 - 37
Sky & Telescope - June 2020 - 38
Sky & Telescope - June 2020 - 39
Sky & Telescope - June 2020 - 40
Sky & Telescope - June 2020 - 41
Sky & Telescope - June 2020 - 42
Sky & Telescope - June 2020 - 43
Sky & Telescope - June 2020 - 44
Sky & Telescope - June 2020 - 45
Sky & Telescope - June 2020 - 46
Sky & Telescope - June 2020 - 47
Sky & Telescope - June 2020 - 48
Sky & Telescope - June 2020 - 49
Sky & Telescope - June 2020 - 50
Sky & Telescope - June 2020 - 51
Sky & Telescope - June 2020 - 52
Sky & Telescope - June 2020 - 53
Sky & Telescope - June 2020 - 54
Sky & Telescope - June 2020 - 55
Sky & Telescope - June 2020 - 56
Sky & Telescope - June 2020 - 57
Sky & Telescope - June 2020 - 58
Sky & Telescope - June 2020 - 59
Sky & Telescope - June 2020 - 60
Sky & Telescope - June 2020 - 61
Sky & Telescope - June 2020 - 62
Sky & Telescope - June 2020 - 63
Sky & Telescope - June 2020 - 64
Sky & Telescope - June 2020 - 65
Sky & Telescope - June 2020 - 66
Sky & Telescope - June 2020 - 67
Sky & Telescope - June 2020 - 68
Sky & Telescope - June 2020 - 69
Sky & Telescope - June 2020 - 70
Sky & Telescope - June 2020 - 71
Sky & Telescope - June 2020 - 72
Sky & Telescope - June 2020 - 73
Sky & Telescope - June 2020 - 74
Sky & Telescope - June 2020 - 75
Sky & Telescope - June 2020 - 76
Sky & Telescope - June 2020 - 77
Sky & Telescope - June 2020 - 78
Sky & Telescope - June 2020 - 79
Sky & Telescope - June 2020 - 80
Sky & Telescope - June 2020 - 81
Sky & Telescope - June 2020 - 82
Sky & Telescope - June 2020 - 83
Sky & Telescope - June 2020 - 84
Sky & Telescope - June 2020 - Cover3
Sky & Telescope - June 2020 - Cover4
https://www.nxtbook.com/nxtbooks/aas/st_202012
https://www.nxtbook.com/nxtbooks/aas/st_202011
https://www.nxtbook.com/nxtbooks/aas/st_202010
https://www.nxtbook.com/nxtbooks/aas/st_202009
https://www.nxtbook.com/nxtbooks/aas/st_202008
https://www.nxtbook.com/nxtbooks/aas/st_202007
https://www.nxtbook.com/nxtbooks/aas/st_202006
https://www.nxtbook.com/nxtbooks/aas/st_202005
https://www.nxtbook.com/nxtbooks/aas/st_202004
https://www.nxtbook.com/nxtbooks/aas/st_202003
https://www.nxtbook.com/nxtbooks/aas/st_202002
https://www.nxtbook.com/nxtbooks/aas/st_202001
https://www.nxtbook.com/nxtbooks/aas/st_201912
https://www.nxtbook.com/nxtbooks/aas/st_201911
https://www.nxtbook.com/nxtbooks/aas/st_201910
https://www.nxtbook.com/nxtbooks/aas/st_201909
https://www.nxtbook.com/nxtbooks/aas/st_201908
https://www.nxtbook.com/nxtbooks/aas/st_201907
https://www.nxtbook.com/nxtbooks/aas/st_201906
https://www.nxtbook.com/nxtbooks/aas/st_201905
https://www.nxtbook.com/nxtbooks/aas/st_201904
https://www.nxtbook.com/nxtbooks/aas/st_201903
https://www.nxtbook.com/nxtbooks/aas/st_201902
https://www.nxtbook.com/nxtbooks/aas/st_201901
https://www.nxtbook.com/nxtbooks/aas/st_201812
https://www.nxtbook.com/nxtbooks/aas/st_201811
https://www.nxtbook.com/nxtbooks/aas/st_201810
https://www.nxtbook.com/nxtbooks/aas/st_201809
https://www.nxtbook.com/nxtbooks/aas/st_201808
https://www.nxtbook.com/nxtbooks/aas/st_201807
https://www.nxtbook.com/nxtbooks/aas/st_201806
https://www.nxtbook.com/nxtbooks/aas/st_201805
https://www.nxtbook.com/nxtbooks/aas/st_201804
https://www.nxtbook.com/nxtbooks/aas/st_201803
https://www.nxtbook.com/nxtbooks/aas/st_201802
https://www.nxtbook.com/nxtbooks/aas/st_201801
https://www.nxtbook.com/nxtbooks/aas/st_201712
https://www.nxtbook.com/nxtbooks/aas/st_201711
https://www.nxtbook.com/nxtbooks/aas/st_201710
https://www.nxtbook.com/nxtbooks/aas/st_201709
https://www.nxtbook.com/nxtbooks/aas/st_201708
https://www.nxtbook.com/nxtbooks/aas/st_201707
https://www.nxtbook.com/nxtbooks/aas/st_201706
https://www.nxtbook.com/nxtbooks/aas/st_201705
https://www.nxtbook.com/nxtbooks/aas/st_201704
https://www.nxtbook.com/nxtbooks/aas/st_201703
https://www.nxtbook.com/nxtbooks/aas/st_201702
https://www.nxtbook.com/nxtbooks/aas/st_201701
https://www.nxtbook.com/nxtbooks/aas/st_201612
https://www.nxtbook.com/nxtbooks/aas/st_201611
https://www.nxtbook.com/nxtbooks/newtrack/st_201612
https://www.nxtbook.com/nxtbooks/aas/st_201610
https://www.nxtbook.com/nxtbooks/aas/st_201609
https://www.nxtbook.com/nxtbooks/aas/st_201608
https://www.nxtbook.com/nxtbooks/aas/st_201607
https://www.nxtbook.com/nxtbooks/aas/st_201606
https://www.nxtbook.com/nxtbooks/aas/st_201605
https://www.nxtbook.com/nxtbooks/aas/st_201604
https://www.nxtbook.com/nxtbooks/aas/st_201603
https://www.nxtbook.com/nxtbooks/aas/st_201602
https://www.nxtbook.com/nxtbooks/aas/st_201601
https://www.nxtbook.com/nxtbooks/aas/st_201512
https://www.nxtbook.com/nxtbooks/aas/st_201511
https://www.nxtbook.com/nxtbooks/aas/st_201510
https://www.nxtbook.com/nxtbooks/aas/st_201509
https://www.nxtbook.com/nxtbooks/aas/st_201508
https://www.nxtbook.com/nxtbooks/aas/st_201507
https://www.nxtbook.com/nxtbooks/aas/st_201506
https://www.nxtbook.com/nxtbooks/aas/st_201505
https://www.nxtbook.com/nxtbooks/aas/st_201504
https://www.nxtbook.com/nxtbooks/aas/st_201503
https://www.nxtbook.com/nxtbooks/aas/st_201502
https://www.nxtbook.com/nxtbooks/aas/st_201501
https://www.nxtbook.com/nxtbooks/aas/st_201412
https://www.nxtbook.com/nxtbooks/aas/st_201411
https://www.nxtbook.com/nxtbooks/aas/st_201410
https://www.nxtbook.com/nxtbooks/aas/st_201409
https://www.nxtbook.com/nxtbooks/aas/st_201408
https://www.nxtbook.com/nxtbooks/aas/st_201407
https://www.nxtbook.com/nxtbooks/aas/st_201406
https://www.nxtbook.com/nxtbooks/aas/st_mars
https://www.nxtbook.com/nxtbooks/aas/st_201405
https://www.nxtbook.com/nxtbooks/aas/st_201404
https://www.nxtbook.com/nxtbooks/aas/st_201403
https://www.nxtbook.com/nxtbooks/aas/st_201402
https://www.nxtbook.com/nxtbooks/aas/st_201401
https://www.nxtbook.com/nxtbooks/aas/st_201312
https://www.nxtbook.com/nxtbooks/aas/st_201311
https://www.nxtbook.com/nxtbooks/aas/st_201310
https://www.nxtbook.com/nxtbooks/aas/st_201309
https://www.nxtbook.com/nxtbooks/aas/st_201308
https://www.nxtbook.com/nxtbooks/aas/st_201307
https://www.nxtbook.com/nxtbooks/aas/st_201306
https://www.nxtbook.com/nxtbooks/aas/st_201305
https://www.nxtbook.com/nxtbooks/aas/st_201304
https://www.nxtbook.com/nxtbooks/aas/st_201303
https://www.nxtbook.com/nxtbooks/aas/st_201302
https://www.nxtbook.com/nxtbooks/aas/st_201301
https://www.nxtbook.com/nxtbooks/aas/st_201212
https://www.nxtbook.com/nxtbooks/aas/st_201211
https://www.nxtbook.com/nxtbooks/aas/st_201210
https://www.nxtbook.com/nxtbooks/aas/st_201209
https://www.nxtbook.com/nxtbooks/aas/st_201208
https://www.nxtbook.com/nxtbooks/aas/st_201207
https://www.nxtbook.com/nxtbooks/aas/st_201206
https://www.nxtbook.com/nxtbooks/aas/st_201205
https://www.nxtbook.com/nxtbooks/aas/st_201204
https://www.nxtbook.com/nxtbooks/aas/st_201203
https://www.nxtbook.com/nxtbooks/aas/st_201202
https://www.nxtbook.com/nxtbooks/aas/st_201201
https://www.nxtbook.com/nxtbooks/aas/st_201112
https://www.nxtbook.com/nxtbooks/aas/st_201111
https://www.nxtbook.com/nxtbooks/aas/st_201110
https://www.nxtbook.com/nxtbooks/aas/st_201109
https://www.nxtbook.com/nxtbooks/aas/st_201108
https://www.nxtbook.com/nxtbooks/aas/st_201107
https://www.nxtbook.com/nxtbooks/aas/st_201106
https://www.nxtbook.com/nxtbooks/aas/st_201105
https://www.nxtbook.com/nxtbooks/aas/st_201104
https://www.nxtbook.com/nxtbooks/aas/st_201103
https://www.nxtbook.com/nxtbooks/aas/st_201102
https://www.nxtbook.com/nxtbooks/aas/st_201101
https://www.nxtbook.com/nxtbooks/aas/st_201012
https://www.nxtbook.com/nxtbooks/aas/st_201011
https://www.nxtbook.com/nxtbooks/aas/st_201010
https://www.nxtbook.com/nxtbooks/aas/st_201009
https://www.nxtbook.com/nxtbooks/aas/st_201008
https://www.nxtbook.com/nxtbooks/aas/st_201007
https://www.nxtbook.com/nxtbooks/aas/st_201006
https://www.nxtbook.com/nxtbooks/aas/st_201005
https://www.nxtbook.com/nxtbooks/aas/st_201004
https://www.nxtbook.com/nxtbooks/aas/st_201003
https://www.nxtbook.com/nxtbooks/aas/st_201002
https://www.nxtbook.com/nxtbooks/aas/st_201001
https://www.nxtbookmedia.com