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A circumpolar constellation, Draco revolves around the North Pole and is only present in the northern hemisphere. Its head is the easiest way to spot it in the night sky, consisting of four stars in a trapezoid and burning brightly just north of Hercules. This tail, then slithers through the sky and ends between the Big and Little Dippers. In Latin, Draco means ‘the dragon’ and is clearly visible in the month of July. It is a constellation of the Ursa Major family and was first catalogued by the Greek astronomer Ptolemy in the 2nd century. Let us discuss this constellation in detail.

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Which stars comprise the constellation?

The major stars of the constellation include:

Etamin (Eltanin)–y Draconis (Gamma Draconis): It is the brightest star in this constellation. It a visual magnitude of about 2.3617 and is about 154.3 light years away from the solar system. It is basically an evolved giant, which is about 471 times brighter than the sun. It also comprises of a companion with a visual magnitude of 13.4.
Aldibain (Eta Draconis): It is the second brightest star in this constellation. It also comprises of a visual companion, a main sequence star with a magnitude of 8.8. The estimated age of Aldibain is to be 550 million years and it is about 60 times brighter than the sun. With a visual magnitude of 2.73, it is about 92.1 light years away from the solar system.
Rastaban (Beta Draconis): Rastaban is the third brightest star in this constellation. It is a yellow star, which is halfway between the bright giant and supergiant evolutionary stage. Rastaban is about 950 times brighter than the sun. With a visual magnitude of 2.79, it is about 380 light years away.
Altais (Delta Draconis): Altais is basically a yellow giant star. The estimated age of Altais is believed to be 800 million years. It is about 59 times brighter than the sun. It has a magnitude of 3.07 and is about 97.4 light years away from the earth.
Aldhibah (Zeta Draconis): Aldhibah is a giant star in this constellation. With a visual magnitude of 3.17, it is about 330 light years away. Aldhibah is about 148 times brighter than the sun.
Edasich (Iota Draconis): Edasich is a giant star in this constellation. The star has a visual magnitude of about 3.290 and is about 101.2 light years away from the earth. In the year 2002, a planet was discovered in its orbit. It is about 55 times brighter than the sun.
Batentaban Borealis (Chi Draconis): It is a star system comprising of a yellow–white star with a visual magnitude of 3.68 and an orange star with a magnitude of 5.67. The combined magnitude of the system is 3.570.
Batentaban Australis (Phi Draconis): It is basically a multiple star system with a visual magnitude of 4.2004 and is about 300 light years away. It is composed of hydrogen fusing dwarfs, including two bright components which orbit each other with a period of 307.8 years.
Thuban (Alpha Draconis): Thuban is a white giant in this constellation. It has a visual magnitude of 3.6452 and is about 303 light years away. It is about 250 times brighter than the sun. Being a double star, its companion is either a white or a red dwarf.
Grumium (Xi Draconis): It has a magnitude of 3.75 and is about 112.5 light years away.
Gianfar (Lambda Draconis): It has a magnitude of 4.1 and is about 334 light years away.

The other notable stars in this Constellation are Tyl (Epsilon Draconis), Kappa Draconis, Theta Draconis, Draconis (Omicron Draconis), Alsafi (Sigma Draconis), 42 Draconis, Kuma (Nu Draconis), Arrakis (Mu Draconis), 26 Draconis, BY Draconis, Struve 2398 (Gliese 725), Kepler–10 and GD 356.

Does it contain any deep sky objects or galaxies?

A few deep sky objects in Draco include:

Cat’s Eye Nebula (Caldwell 6): It is a planetary nebula in this constellation with a visual magnitude of about 9.8 and is about 3300 light years away from the earth. It is considered to be one of the most complex nebulae ever discovered. The Cat’s Eye Nebula is about 10,000 times brighter than the sun.
Spindle Galaxy–Messier 102–NGC 5866: It is basically a spiral or lenticular galaxy discovered in the year 1788. Spindle Galaxy has a visual magnitude of about 10.7 and is about 50 million years away. This galaxy is known for its extended disk of dust, which contains a ring like structure.
Draco Dwarf Galaxy: It is basically a spheroidal galaxy in this constellation. With a visual magnitude of 10.9, it is about 26,000 light years away. It is one of the faintest satellite galaxies of the Milky Way. It is believed that this galaxy contains large amounts of dark matter.
Abell 2218: It is basically a galaxy cluster in this constellation, about 2.345 million light years away. Abell 2218 comprises of thousands of galaxies.
Tadpole Galaxy–Arp 188: It is a disrupted spiral galaxy in this constellation. It has a visual magnitude of about 14.4 and is about 400 million light years away from the solar system. Arp 188 is well known for its enormous trail of stars, around 289 thousand light years long. It comprises of a number of clusters of bright, massive blue stars.
Q1634+706: It is basically a quasar (a massive and extremely remote celestial object emitting exceptionally large amount of energy) in this constellation. It is known for being the most distant object in the sky. It has a visual magnitude of about 14.4 and is around 12.9 billion light years away.
NGC 6340: It is a spiral galaxy in this constellation and has a visual magnitude of 11.9. It is about 52 million light years away.
NGC 5879: It is a spiral galaxy in this constellation with a magnitude of 12.4. It was discovered by William Herschel in 1788.

The other notable deep sky objects in this constellation are PGC 39058, NGC 6503, NGC 4236, NGC 4319 and Markarian 205.

What is its position in the galaxy?

Draco lies in the third quadrant of the northern hemisphere and can be seen at latitudes between +90° and -15°.

How much space does it occupy in the sky?

It occupies an area of 1083 square degrees, making it the eight largest constellation in the night sky.

What is the cultural or mythological significance of Draco?

There are several myths associated with the constellation Draco. One of them is about the 12 labours of Heracles, which is represented by the neighbouring constellation Hercules. In this myth, Draco is represented as Ladon, the dragon that guarded the golden apples in the gardens of the Hesperides. However, on the other hand, the Roman mythology states that Draco was one of the Giant Titans who warred with the Olympian gods for ten years. The goddess Minerva killed him in the battle and threw him into the sky, where it froze around the North Pole.

Which are its neighbouring constellations?

Draco is surrounded by constellations such as Bootes, Camelopardalis, Cepheus, Cygnus, Hercules, Lyra, Ursa Major and Ursa Minor.

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