Sky and Telescope - December 2017 - 35

a dense molecular cloud that's part of the Huygens region and
lies behind the thin, relatively transparent front surface of
the bubble. However, under normal observing conditions the
only color I've detected in Orion S or the Bright Bar is the
turquoise-green tint of the entire Huygens region.
There are several Herbig-Haro (HH) objects in the Huygens
region. These are essentially newly born stars, or protostars,
that exhibit jet-like features. I could make out HH 202, HH
203, HH 204, and HH 524, but I could only unambiguously
identify the latter distinctly. HH 202 was an inconspicuous
smudge northwest of Orion S, HH 203 appeared as a slightly
brighter area of nebulosity protruding off the Bright Bar, and
HH 204 was barely detectable as a faint spot. Contributing to
the difficulty of observing HH 203 and HH 204 is the nearby
magnitude-5.1 star Theta2 Orionis A.
Along the northwest-to-southeast perimeter of the Huygens region are streamers of gas that appear to be flowing out
of the H II canyon. The most prominent are on the northwest
and west borders. Visually, they remind me of the jets produced by active comets as they approach the Sun. They're not
only a fascinating detail in their own right in this rich region,
but they also provide clues to the forces shaping M42.
The Fish Mouth, or Dark Bay, is the most prominent dark
nebula of the Orion Nebula. Not perfectly opaque, it only
partially obscures the Huygens region on the east. It has a
range of subtle internal details along its length, and its borders range from sharply defined at its north edge to indistinct
for much of the rest of its length.

south off the northwest tip of this wing is a series of turbulent, subtle bows and curls that delineate the inner bubble.
They're difficult to see on most nights and won't be easily
visible unless you have superb observing conditions.
These grayish tendrils form a delicate arch of rippling,
entwined wisps and whirls that connect the tips of the northwest and southeast wings in this faintest feature of M42. Once
you have seen this convoluted arch complete the full M42
bubble, you will get a sense for how large an object M42 really
is, and you will get an idea of what 24 light-years looks like
from 1,400 light-years away.

M43
Even though it's often overlooked, M43 offers visual delights
of its own. Through a telescope it appears to be a separate
object from M42, but deep exposures show that it's clearly
part of the same nebula complex.
¢ HH OBJECTS ¢ STARS ¢ NEBULAE

HH 201

Dark Bay
HH 202

Trapezium

HH 510
O

ri

on

S

HH 524

ESO / PE TER WEILBACHER E T A L.

M42's Bat Wings
Two other notable features of M42 are the Bat Wings, which
extend northwest and southeast from the Huygens region. A
section of the southeast feature is evocative of a bat wing, but
overall the "wings" look more like flower petals to me. The
inner edge of the southeast wing is clearly defined and has a
unique rust-brown color. Along the wings, we're looking at the
front surface of M42's bubble mostly edge-on, which means
we're looking through more material in our line of sight. From
the side, we'd probably see through the layers like we do the
rest of the bubble's relatively transparent front surface.
The wings begin near the northeast terminus of the Huygens region. They're well-defined along much of their length,
but they blend almost seamlessly with the Huygens region at
their common base.
Towards the end of the southeast wing, just to the right
of the bat wing feature, you'll see a much fainter appendage
nearly perpendicular to the wing that looks somewhat like a
tooth or a claw. Further south is a larger and fainter version.
There's also a faint streamer that parallels the inner edge of
the southeast wing, but it's not of the same dark rust-brown
color. On a great night it has a rosy tint like much of the
interior of the M42 bubble, which is best seen to the south of
the Huygens region.
The northwest wing shares the dark rust-brown color of
the southeast wing but isn't quite as prominent. Flowing

θ 2 Ori B

Bright Bar

θ 2 Ori A

SW cloud

HH 203

HH 204

LL Ori

p MUSE OBSERVES HUYGENS This Multi Unit Spectroscopic Explorer
(MUSE) image of the Huygens region highlights the rich panoply of features in the Orion Nebula region.

Theta Orionis
The Trapezium Multiple Star System
Star

Mag(v)

Notes

A

6.7

Eclipsing binary in 3-star system

B

8.0

Eclipsing binary in 5-star system

C

5.1

Spectroscopic binary star

D

6.7

Double star

E

11.1

Spectroscopic binary star

F

10.1

Binary star

G

13.7

Single star

Data are taken from recent catalogs, with additions by Jerry Lodriguss.

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

35


http://www.skyandtelescope.com

Sky and Telescope - December 2017

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

Contents
Sky and Telescope - December 2017 - Cover1
Sky and Telescope - December 2017 - Cover2
Sky and Telescope - December 2017 - 1
Sky and Telescope - December 2017 - Contents
Sky and Telescope - December 2017 - 3
Sky and Telescope - December 2017 - 4
Sky and Telescope - December 2017 - 5
Sky and Telescope - December 2017 - 6
Sky and Telescope - December 2017 - 7
Sky and Telescope - December 2017 - 8
Sky and Telescope - December 2017 - 9
Sky and Telescope - December 2017 - 10
Sky and Telescope - December 2017 - 11
Sky and Telescope - December 2017 - 12
Sky and Telescope - December 2017 - 13
Sky and Telescope - December 2017 - 14
Sky and Telescope - December 2017 - 15
Sky and Telescope - December 2017 - 16
Sky and Telescope - December 2017 - 17
Sky and Telescope - December 2017 - 18
Sky and Telescope - December 2017 - 19
Sky and Telescope - December 2017 - 20
Sky and Telescope - December 2017 - 21
Sky and Telescope - December 2017 - 22
Sky and Telescope - December 2017 - 23
Sky and Telescope - December 2017 - 24
Sky and Telescope - December 2017 - 25
Sky and Telescope - December 2017 - 26
Sky and Telescope - December 2017 - 27
Sky and Telescope - December 2017 - 28
Sky and Telescope - December 2017 - 29
Sky and Telescope - December 2017 - 30
Sky and Telescope - December 2017 - 31
Sky and Telescope - December 2017 - 32
Sky and Telescope - December 2017 - 33
Sky and Telescope - December 2017 - 34
Sky and Telescope - December 2017 - 35
Sky and Telescope - December 2017 - 36
Sky and Telescope - December 2017 - 37
Sky and Telescope - December 2017 - 38
Sky and Telescope - December 2017 - 39
Sky and Telescope - December 2017 - 40
Sky and Telescope - December 2017 - 41
Sky and Telescope - December 2017 - 42
Sky and Telescope - December 2017 - 43
Sky and Telescope - December 2017 - 44
Sky and Telescope - December 2017 - 45
Sky and Telescope - December 2017 - 46
Sky and Telescope - December 2017 - 47
Sky and Telescope - December 2017 - 48
Sky and Telescope - December 2017 - 49
Sky and Telescope - December 2017 - 50
Sky and Telescope - December 2017 - 51
Sky and Telescope - December 2017 - 52
Sky and Telescope - December 2017 - 53
Sky and Telescope - December 2017 - 54
Sky and Telescope - December 2017 - 55
Sky and Telescope - December 2017 - 56
Sky and Telescope - December 2017 - 57
Sky and Telescope - December 2017 - 58
Sky and Telescope - December 2017 - 59
Sky and Telescope - December 2017 - 60
Sky and Telescope - December 2017 - 61
Sky and Telescope - December 2017 - 62
Sky and Telescope - December 2017 - 63
Sky and Telescope - December 2017 - 64
Sky and Telescope - December 2017 - 65
Sky and Telescope - December 2017 - 66
Sky and Telescope - December 2017 - 67
Sky and Telescope - December 2017 - 68
Sky and Telescope - December 2017 - 69
Sky and Telescope - December 2017 - 70
Sky and Telescope - December 2017 - 71
Sky and Telescope - December 2017 - 72
Sky and Telescope - December 2017 - 73
Sky and Telescope - December 2017 - 74
Sky and Telescope - December 2017 - 75
Sky and Telescope - December 2017 - 76
Sky and Telescope - December 2017 - 77
Sky and Telescope - December 2017 - 78
Sky and Telescope - December 2017 - 79
Sky and Telescope - December 2017 - 80
Sky and Telescope - December 2017 - 81
Sky and Telescope - December 2017 - 82
Sky and Telescope - December 2017 - 83
Sky and Telescope - December 2017 - 84
Sky and Telescope - December 2017 - Cover3
Sky and Telescope - December 2017 - Cover4
https://www.nxtbook.com/nxtbooks/aas/st_202405
https://www.nxtbook.com/nxtbooks/aas/st_202404_qr
https://www.nxtbook.com/nxtbooks/aas/st_202404
https://www.nxtbook.com/nxtbooks/aas/st_202403
https://www.nxtbook.com/nxtbooks/aas/st_202402
https://www.nxtbook.com/nxtbooks/aas/st_202401_aus
https://www.nxtbook.com/nxtbooks/aas/st_202401
https://www.nxtbook.com/nxtbooks/aas/st_202312_aus
https://www.nxtbook.com/nxtbooks/aas/st_202312
https://www.nxtbook.com/nxtbooks/aas/st_202311
https://www.nxtbook.com/nxtbooks/aas/st_202310
https://www.nxtbook.com/nxtbooks/aas/st_202309
https://www.nxtbook.com/nxtbooks/aas/st_202308
https://www.nxtbook.com/nxtbooks/aas/st_202307
https://www.nxtbook.com/nxtbooks/aas/st_202306
https://www.nxtbook.com/nxtbooks/aas/st_202305
https://www.nxtbook.com/nxtbooks/aas/st_202304
https://www.nxtbook.com/nxtbooks/aas/st_202304_qr
https://www.nxtbook.com/nxtbooks/aas/st_202303
https://www.nxtbook.com/nxtbooks/aas/st_202302
https://www.nxtbook.com/nxtbooks/aas/st_202301
https://www.nxtbook.com/nxtbooks/aas/st_202212
https://www.nxtbook.com/nxtbooks/aas/st_202211
https://www.nxtbook.com/nxtbooks/aas/st_202210
https://www.nxtbook.com/nxtbooks/aas/st_202209
https://www.nxtbook.com/nxtbooks/aas/st_202208
https://www.nxtbook.com/nxtbooks/aas/st_202207
https://www.nxtbook.com/nxtbooks/aas/st_202206
https://www.nxtbook.com/nxtbooks/aas/st_202205
https://www.nxtbook.com/nxtbooks/aas/st_202204
https://www.nxtbook.com/nxtbooks/aas/st_202203
https://www.nxtbook.com/nxtbooks/aas/st_202202
https://www.nxtbook.com/nxtbooks/aas/st_202201
https://www.nxtbook.com/nxtbooks/aas/st_202112
https://www.nxtbook.com/nxtbooks/aas/st_202111
https://www.nxtbook.com/nxtbooks/aas/st_202110
https://www.nxtbook.com/nxtbooks/aas/st_202109
https://www.nxtbook.com/nxtbooks/aas/st_202108
https://www.nxtbook.com/nxtbooks/aas/st_202107
https://www.nxtbook.com/nxtbooks/aas/st_202106
https://www.nxtbook.com/nxtbooks/aas/st_202105
https://www.nxtbook.com/nxtbooks/aas/st_202104
https://www.nxtbook.com/nxtbooks/aas/st_202103
https://www.nxtbook.com/nxtbooks/aas/st_202102
https://www.nxtbook.com/nxtbooks/aas/st_202101
https://www.nxtbook.com/nxtbooks/aas/skywatch_2021
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/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