Observing Orion

Presentation to MAS Feb 5, 2009

Bill Kocken

What’s wrong with this Picture?

Consellation LoreThe 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.html

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 Arp Galaxy List Observing List

Class Primary ID Alt ID Mag SizeSky Atlas 2000 Chart Page Class Primary IDAlt ID Mag Size

Sky Atlas 2000 Chart Page

Neb Great Orion Nebula M 42 4 90.0' 11 Gal Arp 52 PGC 17109 15.6 42"x 26" 11Neb M 43 M 43 9 20.0' 11 Gal NGC 1875 Arp 327 14.7 34"x 24" 11Neb M 78 M 78 8 8.0' 11

Herschel 400 Observing List Herschel - II Observing List

Class Primary ID Alt ID Mag SizeSky Atlas 2000 Chart Page Class Primary IDAlt ID Mag Size

Sky Atlas 2000 Chart Page

PNe NGC 2022 PN G196.6-10.9 12.4 19" 11 Gal NGC 1762 PGC 16654 13.3 1.7'x 1.1' 11Neb NGC 1788 11 Neb NGC 1990 50.0' 11Neb NGC 1999 11 Neb NGC 2023 10.0' 11Neb Flame Nebula 11 Neb NGC 2071 8 7.0' 11Open NGC 1980 OCL 529 2.5 13.0' 11 Open NGC 1662 OCL 470 8 20.0' 11Open 37 Cluster NGC 2169 7 6.0' 11 Open NGC 1663 OCL 461 11Open NGC 2186 OCL 498 9.2 4.0' 11 Open NGC 2112 OCL 509 9.1 11.0' 11Open NGC 2194 OCL 485 10 10.0' 11 Open NGC 1977 OCL 525.1 11

Urban Astronomy Club Observing List

Class Primary ID Alt ID Mag SizeSky Atlas 2000 Chart Page

DVar Theta 1 Ori 5.1 11Neb Great Orion Nebula M 42 4 90.0' 11Open NGC 1981 OCL 525 4.2 24.0' 11Open 37 Cluster NGC 2169 7 6.0' 11

A Big-Picture Chart(from freeware- Cartes du Ciel)

Tonight’s Objects

NGC2169NGC 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.

NGC2194NGC 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

NGC2022NGC 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?

NGC2112NGC 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 2-276Coe 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 2024The 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 34The 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 friendsAlmost 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.