Orion is a constellation
also known as the HUNTER in Greek mythology. Orion is located on the celestial equator and is visible throughout the world.
[hide][top]Observing the Constellation Orion
Orion, the HUNTER is thought by many to be the finest and most brilliant constellation in the sky, and the only one in the north containing two 1m stars.
Its brilliant stars are found on the celestial equator and are visible throughout the world, making this constellation globally recognized.
In the northern hemisphere Orion is visible in the evening from November to April. It is one of the most conspicuous, and most recognizable constellations in the night sky.
There is a well-defined quadrilateral. The 1m star farthest to the northeast is Betelgeuze, and its companion, 2m, some 7 west of it, is Bellatrix.
These are in the shoulders. The other two are 15 south of these. Rigel, a 1m star, is farthest southwest. In the center are three remarkable stars in line, very near together, forming the belt, while suspended from it is the sword, composed of a dim line of stars pointing downward. In front of the hero, who faces the Bull in a menacing attitude, and almost south of Aldebaran, is a semi-circle of dim stars forming the lion-skin shield.
[hide][top]The Myth of the Constellation Orion
Orion, the son of Neptune, was the greatest hunter in the world. He boasted that he could conquer any animal, whereupon a scorpion rose from the earth and stung him to death ; and he still seems to fear that creature, for this constellation sets at the rising of Scorpion. The constellation Orion is mentioned in the books of Job and Amos, and in the writings of Homer and Virgil.
According to the most common contemporary imagery: Orion is standing next to the river Eridanus
with his two hunting dogs Canis Major
and Canis Minor
, fighting Taurus the bull. Other prey of his, such as Lepus
the hare, can be found nearby.
A group of three faint stars outlines the head of Orion. His right shoulder is marked by the deep-red, first-magnitude star Betelgeuze
(meaning armpit), and his left shoulder by the bright white star Bellatrix, The Amazon.
Orion stands facing Taurus
, The Bull, and brandishes in his right hand a club, outlined by a number of faint stars extending from Betelgeuze
toward the northeast. The top of the club lies near the tips of the horns of Taurus. In his left hands he holds up a lion's skin, which we can trace in another curving line of faint stars to the west and northwest of Bellatrix. The brilliant, blue-white, first-magnitude star Rigel lies in the left foot, and the second-magnitude star Saiph, a little to the east of Rigel, is in the right knee. Three evenly spaced stars lying in a straight line that is exactly three degrees in length form the Belt of Orion, and from the Belt hangs the Sword of Orion, outlined by three faint stars.
There are three stars in the Belt of Orion, which is about three degrees in length, and which adds so strikingly to the picturesqueness of the constellation, are named, respectively, beginning with the northernmost, Mintaka, Alnilam, and Alnita. Their Greek letter designations, in the same order, are Delta, Epsilon, and Zeta. The first two are white, the third slightly yellowish.
In the right knee is a star of near the third magnitude called Saiph, or Eta. Saiph, Rigel, Bellatrix, and Betelgeuse mark the corners of an irregular parallelogram, about eighteen degrees in its greatest length, and having the Belt in its centre.
Below the Belt hangs the Sword made conspicuous by a short row of stars of the fourth and fifth mag nitudes, the lowermost of which, Iota , is rather brighter than fourth magnitude. The middle star, Theta, is involved in misty light. This light comes from the celebrated Great Nebula of Orion also known as M42
42), one of the most astonishing objects in the firmament of heaven.
The central star in the Sword appears somewhat blurred and is the multiple star Theta, in the midst of the great Orion nebula
, the finest object of its kind in the heavens. Entangled in the meshes of this glowing nebula are a number of brilliant stars or suns, appearing to us as faint stars because of their great distance. The star Theta, in the heart of the nebula, is seen with a powerful telescope
to consist of six stars; that is, it is a sextuple star. Even with a small telescope, four of these stars can readily be seen, arranged in the form of a small trapezium. The lowest star in the Sword is a triple star, and the entire constellation abounds in double, triple, and multiple stars.
A good binocular shows this nebula M42, and in a telescope its appearance is wonderful beyond description. A third-magnitude star, Eta, below Mintaka, and making a right angle with the line of the Belt, indicates the handle of the Sword.
The Head of Orion is represented by a group of stars, somewhat crowded in appearance, the principal member of which is Lambda, of the third magnitude. The Arabs called the head of Orion Al Hakah, meaning a White Spot.
The uplifted Club of Orion, and his right hand which holds it, contain five fifth magnitude stars and several of the sixth magnitude. The upper end of the Club is almost on a level with the point of the southern horn of Taurus. The Lion's Hide which Orion bears on his left arm, like a shield, contains four stars of the fourth magni tude, two of the fifth, and about ten of the sixth, which impart to it a curious glimmer. Orion contains altogether two stars of the first magnitude (really brighter than first magnitude); four of the second; four of the third; three of the fourth ; twenty-four of the fifth ; and a great number of the sixth. According to early observations, there were seventy eight stars visible to the unaided vision, but most eyes do not distinctly discern so many. A telescope reveals many hundreds of stars.
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[hide][top]Notable Objects in the Constellation Orion
Orion, sometimes subtitled The Hunter, is a wonderfully rich constellation. Notable DSO
s in Orion include M42, M78
, and the running man nebula.
[hide][top]Double Stars in the Constellation Orion
In telescopic objects Orion is wonderfully rich and includes many double stars
. Most famous of its doubles is Rigel. The companion may be seen with a three-inch telescope. Its distance is 9.5"; color, deep blue; magnitude, eight — a most beautiful object.
Alnita in the Belt is a triple; magnitudes, second, sixth, and tenth; distances, 2. 5" and 56" ; colors, yellowish white, grayish purple, pale blue.
Delta in the Belt is double; magnitudes, second and seventh; distance, 53" ; colors, white and greenish white.
Sigma is multiple, the telescope showing eight or ten stars varying from the fourth to the tenth or eleventh magnitudes, and exhibiting divers tints, one star of the seventh magnitude being described as "grape red."
Theta in the Sword is quadruple, and the telescope shows it surrounded with the Great Nebula, a true wonder-cloud which can be very well seen with a three-inch telescope or binoculars.
Lambda in the Head is double; magnitudes, three-and-a-half and sixth; distance 4" ; colors, light yellow and reddish.
Orion also contains many doubles which are not visible, or not easily visible, as single stars to the naked eye.
[hide][top]Nebulae and Galaxies in Orion
The whole constellation is enveloped in a gigantic nebula, traces of which may be seen with powerful telescopes
, but which only reveals itself in its entirety in long exposure photography.
credit to http://apod.nasa.gov
[hide][top]List of Messier Objects in the Constellation Orion
|NGC ||IC ||Messier ||List ||Name ||Const ||Type ||Mag |
|1976 || ||M42 || ||Orion nebula ||Orion ||OC/neb ||4 |
|1981 || || || || ||Orion ||OC ||4.2 |
|1982 || ||M43 || ||North portion of O. nb ||Orion ||OC/neb ||7 |
|2068 || ||M78 || ||Reflective nebula ||Orion ||ReN ||8 |