Orion – The Hunter

 

 

 


The constellation Orion became most famous for its nebula. The Messier database has detailed information about The Large Orion Nebula M 42 and M 43, the DeMairan nebula, which is a part of the Orion Nebula.

 

Mythology

 

Greco-Roman (Roman names are shown in parentheses)

 

There are many versions of the story of Orion, the two main ones being as follows:

 

Version one:

Orion's mother was Euryale, the Amazon queen, and his father was Poseidon (Neptune). He was the world's greatest but biggest-headed hunter.

 

Variation one: He boasted that he could kill any animal, so a tiny scorpion stung and killed him.

 

Variation two: He boasted that he could kill any animal, so the gods sent him an enormous, heavily armoured scorpion for a laugh, which killed him.

 

Version two:

Orion had no parents and was a gift to a pious peasant from Zeus (Jupiter), Poseidon and Hermes (Mercury). He was a great hunter, a blacksmith, and alleged to be able to walk on water. He made the lame blacksmith god Hephaestus (Vulcan) an underground palace beneath Mount Aetna in Sicily, and created coastal defences for the island.

 

He fell in love with Merope, princess of Chios. Her father, King Oenopion wasn't having any of it and would not allow Orion to marry his daughter, even after he killed every wild beast on the island. Orion got drunk and tried to rape Merope, so Oenopion blinded him and left him wandering the shoreline.

 

Variation one: Orion consulted an oracle who told him that the sun god Helios would help him out.

 

Variation two: Orion followed the sound of a cyclops' hammer (a cyclops is a horrible one-eyed giant) and reached Lemnos, where Hephaestus took pity on him and sent him to see Helios with Kedalion on his shoulders as a guide.

 

Helios restored his sight. On his way to get revenge for his blinding, Orion met and stayed with Artemis (Diana), the virgin goddess of hunting, who became very fond of him and was considering marriage. Her brother Apollo was annoyed because she was supposed to be a virgin goddess, so marrying would go against everything she stood for.

 

Variation one: Thus, Apollo sent a scorpion to kill him.

 

Variation two: Thus, when he saw Orion wading in the sea with only his head visible above the waves; he challenged Artemis to shoot with an arrow the distant object bobbing in the sea which was unidentifiable as Orion's head. Unfortunately, Artemis took up the challenge and unwittingly killed him.

 

In all versions, Artemis was reputedly devastated and placed Orion, and when present, the scorpion in the night sky as the constellations Orion and Scorpius. She placed the scorpion opposite him, so that never are the two visible at once.

 

The sky shows him followed by his two fighting dogs, Canis Major and Minor, and fighting a bull, Taurus. Oddly, the bull is completely irrelevant to the story of Orion. The bull represents the form taken by Zeus when he wanted to seduce Europa. She was so impressed by the bull's gentle nature and shining white coat that she climbed on the bull's back to see if she could ride on it (no double entendre intended). The bull ran off and swam to Crete, where Zeus revealed his true form and had his wicked philandering way with her.

 

Egyptian

 

The ancient Egyptians are thought to have identified the constellation of Orion with Osiris, their god of the underworld. It is believed that the three pyramids at Giza were built to mirror the three stars of Orion's belt.

 

Osiris was born in Thebes in Upper Egypt, the heavenly mirror-world that the Egyptians believed existed in the sky, to Nut and Geb. His grandfather Ra made him heir to the throne and so when his father Geb retired he took over as the fourth divine pharaoh and married his sister Isis. He abolished cannibalism, built temples, and taught the people justice and agriculture. This earned him the name Onnophris ('the good one'). He left Egypt to civilise the entire world and Isis did a very good job of running the kingdom in his absence.

 

He met his end when his brother Set got jealous and built him a coffin. He then held an enormous party to which Osiris was invited and offered the coffin to whomever fitted in it best. Obviously, Set had built it especially for his brother and when he got in, Set closed the lid and chucked it and Osiris in the Nile.

 

Isis went to look for Osiris' body and Set took the throne. She found the body far away in Byblos, brought it back and hid it in a marsh. Set found it, tore it up and threw it back into the river. Osiris' genitals got eaten by a fish, but Isis found the rest and wrapped her husband up with bandages to hold him together (the first mummy), and the late Osiris went to underworld to become king of the dead.

 


Position in the Sky

 

 

 

 

 


The Brighter Stars

Name

Bayer/
Flamsteed

Mag.

R.A.

Decl.

Spectrum

Rigel

Beta

0.18

5h 15m

-9° -12"

B8Ia

Betelgeuse

Alpha

0.45

5h 55m

7° 24"

M2Ib

Bellatrix

Gamma

1.64

5h 25m

6° 21"

B2III

Alnilam

Epsilon

1.69

5h 36m

-2° -12"

B0Ia

Alnitak

Zeta

1.74

5h 41m

-2° -57"

O9.5Ib SB

Saiph

Kappa

2.07

5h 48m

-10° -40"

B0.5Iavar

Mintaka

Delta

2.25

5h 32m

-1° -18"

O9.5II

 

Iota

2.75

5h 35m

-6° -55"

O9III

 

Pi3

3.19

4h 50m

6° 58"

F6V

 

Eta

3.35

5h 24m

-3° -24"

B1V + B2

 

Lambda

3.39

5h 35m

9° 56"

O...

 

Tau

3.59

5h 18m

-7° -51"

B5III

 

Pi4

3.68

4h 51m

5° 36"

B2III SB

 

Pi5

3.71

4h 54m

2° 26"

B2III SB

 

Sigma

3.77

5h 39m

-3° -36"

O9.5V...

 

omicron2

4.06

4h 56m

13° 31"

K2III

 

Phi2

4.09

5h 37m

9° 17"

G8III-IV

 

Mu

4.12

6h 2m

9° 39"

Am...

 

29

4.13

5h 24m

-8° -48"

G8III

 

32

4.20

5h 31m

5° 57"

B5V

 

Pi2

4.35

4h 51m

8° 54"

A1Vn

 

Phi1

4.39

5h 35m

9° 29"

B0IV...

 

Chi1

4.39

5h 54m

20° 17"

G0V

 

Nu

4.42

6h 8m

14° 46"

B3IV

 

Xi

4.45

6h 12m

14° 13"

B3IV

 

Rho

4.46

5h 13m

2° 52"

K3III...

 

Pi6

4.47

4h 59m

1° 43"

K2IIvar

 

Omega

4.50

5h 39m

4° 7"

B3IIIe

 


Betelgeuse; alpha Ori

In Arabic Betelgeuse means “Armpit of the central one (or Giant)”. Betelgeus is a variable red giant, its brightness varies from 0.4 in 1.3 in absolute magnitude, it has no set period. It belongs to the 20 brightest stars in the sky. During its pulsations the diameter of the star varies from 300 to 400 times the size of the sun!

 

Rigel; beta Ori

 

It is the leg of the hunter, in Arabic Rigel means “the foot”. It is a blue-white giant of which has an absolute magnitude of 0.08. This makes Rigel the sixth brightest star in the sky and the brightest in Orion. With medium sized telescopes it is possible to distinguish the companion star of Rigel (it is a 7th magnitude star, caught in the glare of Rigel)

 

Mintaka; delta Ori

 

In Arabic it is the “upper end of the girdle”. delta a blue-white star of 2.2 mag with a 7th mag companion.

 

Other stars of interest with binoculars and telescopes:

 

Iota Ori, a 3rd mag and a 7th mag star forming an unequal double; in the same field the wider double

 

Struve 747 can be found - a pair of a 5th mag and a 6th mag star.

 

Lambda Ori, a tight pair of 4th and 6th mag stars.

 

Sigma Ori is a multiple star; with binoculars this a blue-white star of 4 mag and a 7th mag companion can be resolved.

 

NGC 1981, a little cluster of 10 stars including the binary Struve 750, a pair of a 6th mag and a 8th mag star.

 

The multiple star theta1 Ori, the northern star of the deggar of the Hunter is also called the Trapezium; it is located in the heart of the Orion nebula. This group of stars has been formed from the gas of the nebula, which now glows in their light.

 

Zeta Ori (Alnitak), it is a tight double consisting of a 2.02 and 4th magnitude star.

 

Eta Ori is a difficult pair to see as therse stars are 4th and 5th magnitude.

 

 

The Nebulae

M-42 - The Great Nebula. One of the finest sights in the sky, this nebula is easily visible to the naked eye as the 'fuzzy' star in the middle of Orion's sword. It appears distinctly nebulous in binoculars or finder scopes. The brightest region surrounds the four relatively bright stars known as the Trapezium. The region around the Trapezium appears as a cold steel blue colour, wile the wispy regions further away can appear as a soft ruddy pink.

 

 

 

M42 is approximately 1630 light years away. The bright part of the nebula is the glow of many luminous, newborn stars shining on the surrounding gas cloud that they collapsed from. The most important part of the Orion Nebula is the part that can not be seen is the opaque Orion Molecular Cloud. This is a region of very cold gas and has a mass of about 2000 times the mass of the Sun. This gas slowly collapses due to gravitation to form stars. This part of the nebula is visible whenever a new star is formed. M42 is an open cluster.

 

 

 

 

 

 

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M-43, de Mairan's Nebula. This is a diffuse nebula. The dark features along its eastern border are well visible in telescopes starting at about 8 inch. The nebula itself is a fine view even in a 4-inch.

 

 

 

 

 

M-78, diffuse nebula. This is another fine area of nebulosity. It is somewhat fan shaped. NGC's 2064, 2067, and 2071 lie in very close proximity to M-78, and are all nebulous regions as well.

 

 

 


 

Contributors:

 

Samuel George

Alexandra Yannacopoulou

Emma Robinson

 

 

References:

 

www.heavens-above.com

www.nasa.gov

www.afit.edi

Starry Night Backyard Software

www.trailtopobservatory.org