The Orion constellation sits on the equator and is best viewed from December to March. It is a very bright constellation and a favorite in winter.
Orion is easily located in the sky because of its three bright stars, which form the famous “Belt of Orion”. The Belt of Orion also marks the area of the celestial equator.
Betelgeuse is the super red giant star in Orion’s shoulder. Betelgeuse translates from Arabic “the armpit of the central one”. The magnitude is .9. Rigel, “the left leg”, is a blue white super giant star of .3 magnitude.
Bellatrix, “the Amazon star”, is Orion’s other shoulder. It is yellow and is a 2-magnitude star. Delta, Epsilon and Zeta are three equally spaced bright stars forming the belt or girdle of Orion.
Just below the belt of Orion, the Orion Nebula M-42 is visible with the naked eye. The spectacular Horsehead Nebula is here. Orion is best viewed from December to March.
Whoever looks upon the constellation will never forget it. When Orion is on the meridian, it is visible to all the habitable world because it passes over the equator of the Earth. Orion is shown on star maps as a hunter attacking a bull while bearing a sword in his belt, holding a huge club in his right hand and the skin of a lion in his left.
There’s a tight triangle of three small stars in Orion’s head, which forms a larger triangle with the two in his shoulders. In the middle of the constellation are three stars of the 2nd magnitude in Orion’s belt, forming a straight line about 3° in length from northwest to southeast.
These three stars usually are distinguished as the “Three Sisters” because no others exactly resemble them in position or brightness. Sometimes they are called the Three Kings. Ancient husbandmen called them Jacob’s Rod or the Rake. In 1807, the University of Leipsic gave them the name Napoleon.
A common name is the Elland Yard from the fact that the line which unites the three stars in the belt measures just 3° in length, divided equally by the central star, like the feet on a yardstick. That makes it a standard for measuring the distance of stars from each other. A line through the three stars of the belt will point out Pleiades and Hyades on one side and Sirius, “The Dog Star,” on the other.
Orion is also notable for having two meteor showers each year. Th Orionids meteor shower around October 21st. The smaller Northern Chi Orionids peaks around December 10th.
The nearest constellations to Orion are Eridanus, Gemini, Lepus, Monoceros and Taurus.
Right Ascension: 05:32
Diameter (°): 17
Area (square °): 594
Opposition: Dec 15
Size Rank: 26th
Brightness Rank: 4th
Major or notable stars in Orion
Rigel – β Orionis (Beta Orionis, 19 Orionis)
Betelgeuse – α Orionis (Alpha Orionis, 58 Orionis)
Bellatrix – γ Orionis (Gamma Orionis, 24 Orionis)
Orion’s Belt – Mintaka, Alnilam and Alnitak (Delta, Epsilon and Zeta Orionis)
Mintaka – δ Orionis (Delta Orionis, 34 Orionis)
Alnilam – ε Orionis (Epsilon Orionis, 46 Orionis)
Alnitak – ζ Orionis (Zeta Orionis, 50 Orionis)
Saiph – κ Orionis (Kappa Orionis, 53 Orionis)
Hatysa – ι Orionis (Iota Orionis)
Meissa – λ Orionis (Lambda Orionis)
φ Orionis (Phi Orionis)
π Orionis (Pi Orionis)
η Orionis (Eta Orionis)
σ Orionis (Sigma Orionis)
τ Orionis (Tau Orionis)
χ1 Orionis (Chi-1 Orionis)
Deep Sky Objects in Orion
Orion Molecular Cloud Complex
Orion Nebula – Messier 42 (M42, NGC 1976)
De Mairan’s Nebula – Messier 43 (M43, NGC 1982)
Messier 78 (M78, NGC 2068)
The Flame Nebula (NGC 2024)
37 Cluster (NGC 2169)
Monkey Head Nebula (NGC 2174)
Mythology of the Constellation Orion
Orion was the handsome son of Neptune and Queen Euryale, a famous Amazonian huntress. Having the disposition of his mother, he became the greatest hunter in the world, boasting that he could conquer any animal on Earth.
In one myth, Orion fell in love with the seven daughters of Atlas. To save them, the God Zeus scooped them all up and put them in the stars. They can be found in the constellation Taurus and are known as the Pleiades.
In another story, he was blinded by King Oenopion. He asked for help from an oracle, who told him to head west toward the sun. He did so and his vision was restored. He still travels west through the night sky.
The most famous stories about Orion involve the constellation Scorpius. Scorpius sits directly across from Orion, as far away as possible on the celestial sphere.
In one story, he is heard bragging about his ability to vanquish any wild beast. To punish his vanity, a scorpion sprang out of the Earth and killed him with a bite to his foot. Diana requested that he be placed among the stars opposite the Scorpion which had caused his death.
Another story relates the tale of Orion and his pursuit of the Goddess Artemis. In this version, Artemis sent the scorpion to protect herself from his unwanted advances.
In another tale, Artemis and Orion were in love. Apollo, the brother of Artemis sent the scorpion to protect his sister’s vow of chastity.
The Sumerians called Orion “the light of heaven” and represented him as a hero fighting Taurus the bull.
The Latin poet Manilius, who wrote five books on astronomy, said of Orion:
“First after the Twins, see great Orion rise,
His arms extended stretch o’er half the skies
His stride as large, and with a steady pace
He marches on, and measures a vast space;
On each broad shoulder a bright star display’d.
And three obliquely grace his hanging blade.
In his vast head, immrs’d in boundless spheres,
Three stars, less bright, but yet as great, he bears,
But farther off removed, their splendour’s lost;
Thus, grac’d and arm’d he leads the starry host.”