Transcript Observing Orion

Observing Orion
Presentation to MAS
Feb 5, 2009
Bill Kocken
What’s wrong with
this Picture?
Consellation Lore
The Great Hunter. Orion boasted that no animal
could defeat him and he boasted that so
great was his might and skill as a hunter that
he could kill all the animals on the face of
the Earth. Gaea, Goddess of Earth, was
alarmed at such an unecological and
inappropriate statement. She decided that
Orion must be killed just in case he might
one day decide to carry out his boast. So
Gaea sent a giant scorpion to Orion and
ordered the beast to sting Orion. As mighty
as Orion was, after only a brief battle, the
scorpion managed to deliver the hunter a
deadly sting. Scorpius stung Orion on the
heel (at the star Rigel). Orion and the
scorpion were given honored places in the
sky, but they were placed at opposite ends
of the sky dome. Some legends have him
either pursuing Scorpius or fleeing from it.
He is followed by his two dogs Canis Major
and Canis Minor and he is now fighting the
bull Taurus
The ancient Sumerians saw not a man but a
sheep. The name Betelgeuse literally means
"the armpit"; in case of the Sumerians it
meant "the armpit of the sheep."
Source SEDS and
http://www.coldwater.k12.mi.us/lms/planetarium/myth/Orion.ht
ml
Consellation Specifics
Orion is probably the 2nd most
recognized star pattern in the
sky, behind only the Big
Dipper. It lies in and adjacent
to the winter Milky Way and is
home to a vast array of
nebulae and star clusters.
In the Southern Hemisphere,
Orion appears upside down.
Orion’s belt of three bright stars
point to Sirius in Canis Major in
one direction and the Hyades
in Taurus in the other direction.
Orion’s Astronomical League List
Objects
Messier Observing List
Class
Neb
Neb
Neb
Primary ID
Great Orion Nebula
M 43
M 78
Arp Galaxy List Observing List
Alt ID
M 42
M 43
M 78
Mag
Size
4 90.0'
9 20.0'
8 8.0'
Sky Atlas 2000
Chart Page
11
11
11
Herschel 400 Observing List
Class
Primary ID
PNe
NGC 2022
Neb
NGC 1788
Neb
NGC 1999
Neb
Flame Nebula
Open
NGC 1980
Open
37 Cluster
Open
NGC 2186
Open
NGC 2194
Urban Astronomy Club Observing List
Class
DVar
Neb
Open
Open
Primary ID
Theta 1 Ori
Great Orion Nebula
NGC 1981
37 Cluster
Class
Gal
Gal
Primary IDAlt ID
Mag
Size
Arp 52
PGC 17109
15.6 42"x 26"
NGC 1875 Arp 327
14.7 34"x 24"
Sky Atlas 2000
Chart Page
11
11
Herschel - II Observing List
Alt ID
Mag
Size
PN G196.6-10.9 12.4 19"
OCL 529
NGC 2169
OCL 498
OCL 485
Alt ID
M 42
OCL 525
NGC 2169
2.5
7
9.2
10
Mag
13.0'
6.0'
4.0'
10.0'
Size
5.1
4 90.0'
4.2 24.0'
7 6.0'
Sky Atlas 2000
Chart Page
11
11
11
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11
Sky Atlas 2000
Chart Page
11
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11
Class
Gal
Neb
Neb
Neb
Open
Open
Open
Open
Primary IDAlt ID
Mag
Size
NGC 1762 PGC 16654
13.3 1.7'x 1.1'
NGC 1990
50.0'
NGC 2023
10.0'
NGC 2071
8 7.0'
NGC 1662 OCL 470
8 20.0'
NGC 1663 OCL 461
NGC 2112 OCL 509
9.1 11.0'
NGC 1977 OCL 525.1
Sky Atlas 2000
Chart Page
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A Big-Picture Chart
(from freeware- Cartes du
Ciel)
Tonight’s Objects
NGC2169
NGC 2169 is a pretty bright and
pretty small open cluster
located up in Orion’s club.
Approximately 17 stars are
visible in an 8-10” scope at
100x. In a larger scope the
count increases to about 35
although it is difficult to
differentiate all of the cluster’s
members from the general
starfield.
The most fascinating feature of
this cluster is that the 10
brightest stars form a perfect
"37". It is a shame that this is
not M-37, you couldn't miss it.
NGC2194
NGC 2194 is a faint but rich and
compressed open cluster that is
well resolved in larger (16”)
scopes at 150X. The cluster has
a somewhat irregular shape
covering about 8 to 10’. There
are about 50 stars visible.
The overall magnitude is 8.5, so it
makes a fine target for
moderately sized scopes also.
When searching for this cluster, I
kept re-finding NGC2169
NGC2022
NGC 2022 is a small (18”) rather faint
(mag 12.9) planetary nebula located
up near Orion’s head..
Steven Coe writes, “With the 13 inch
Newtonian it is pretty bright, pretty
large, elongated 1.5X1 in a PA of 0
degrees. It is somewhat brighter in
the middle and shows a nice disk at
higher powers. It was spotted at
100X but the central star was never
seen, just a brightening in the
middle. At 330X on a great night I
saw the east side as consistently
brighter than the west side. I called
the color grey in the 13", using my
old 17.5" Dobsonian at 200X, I
observed that this planetary was
greenish”
His description of being elongated
seems to be at odds with other
descriptions. What will you see?
NGC2112
NGC 2112 is an open cluster,
observed as pretty faint, and
only moderately compressed. In
a 12” scope at low power it
shows about 10 stars. In a 16”
scope it shows about 3 dozen
stars.
Coe Says, “In 17.5" f/4.5 scope at
125X the cluster is well resolved
into 40 stars and has one bright
member with the rest of the
cluster having a mottled "cottage
cheese" effect. Averted vision
does bring out a few more
members.”
This cluster is the center of
Barnard’s Loop along Orion’s left
side.
Barnard’s Loop: Sharpless 2-276
Coe writes,
Photos by E.E. Barnard from 100 years ago
show this very large curved arc of
nebulosity that curls around the Belt stars
from Rigel to Betelgeuse. Open cluster
NGC 2112 is right in the middle of this
streamer of nebulosity. I have seen this
object with the naked eye while holding a
2” UHC filter up to the sky on a night I
rated 7/10. It shows just a hint of a very
faint streamer that is very long, hence the
name.
Using the 8X42 binoculars, I could follow the
nebulous streamer for three degrees
above the cluster NGC 2112 and for two
degrees below the cluster. I held the 2 inch
UHC filter in front of one objective of the
binoculars and closed the other eye. This
did help the contrast somewhat, but this is
still a low surface brightness object under
any conditions.
Moving up in aperture to a 4" f/6 RFT refractor
shows it as pretty faint, very large and
very, very elongated. It shows the
nebulosity two fields of view long, 3
degrees above and 3 degrees below the
star cluster.
Flame Nebula: NGC 2024
The bright star Alnitak, the easternmost
star in the Belt of Orion, shines high
energy ultraviolet light into the area
knocking electrons away from the
hydrogen gas that resides there. The
glow results when the electrons and
ionized hydrogen recombine.
Additional dark gas and dust lies in
front of the bright part of the nebula
and this is what causes the dark
network that appears in the center of
the glowing gas.
Despite it’s exotic appearance this is not
a difficult object. It can be detected
in binoculars, although it always
requires good transparency.
In a medium size scope, with an OIII
filter it covers about ½ degree. Use
high enough power to get Alnitak out
of the field of view.
Horsehead Nebula: Barnard 34
The Horsehead Nebula is the famous dark intrusion shown here, sticking into
bright nebula IC 434. The nebula is located just below Alnitak, the star
furthest left on Orion's Belt. The flame nebula is also shown in this photo. It
is one of the most identifiable nebulae because of the shape of its swirling
cloud of dark dust and gases, which is similar to that of a horse's head. It
was first noticed in 1888 by Williamina Fleming on a photographic plate.
The red glow in this photo
originates from hydrogen gas
behind the nebula being ionized
by Alnitak. The darkness of the
Horsehead is caused mostly by
thick dust blocking the glow.
This is very difficult object and
until relatively recently it was
thought to be unobservable by
amateurs. It requires very clear
skies and usually a large scope.
A Hydrogen Beta filter is also
generally required, although some
references suggest that an OIII or
UHC filter can work.
The Orion Nebula: M42 and friends
Almost without a doubt the
most magnificent target for
astronomers everywhere.
It is easily found as a fuzzy
patch below Orion’s belt.
Entire books probably
have been written about
the nebula and the
surrounding region.
What more could I say?
Fabulous.
and there’s more…
This presentation only just
barely scratched the
surface. You could spend
an entire winter season
exploring this fabulous
constellation’s sights.
Now that the worst of the
winter is over (I hope),
get out there and observe
Orion’s wonders.