Draco (constellation)

Draco

Constellation
List of stars in Draco
Abbreviation	Dra
Genitive	Draconis
Right ascension	15
Declination	+75
Area	1083 sq. deg. (8th)
Main stars	14
Bayer/Flamsteed stars	72
Stars with planets	2
Stars brighter than 3.00m	3
Stars within 10.00 pc (32.62 ly)	7
Brightest star	γ Dra (Etamin) (2.23m)
Messier objects	1
Meteor showers	Draconids
Bordering constellations	Boötes Hercules Lyra Cygnus Cepheus Ursa Minor Camelopardalis Ursa Major
Visible at latitudes between +90° and −15°. Best visible at 21:00 (9 p.m.) during the month of July.

Draco (IPA: [ˈdreɪ.koʊ], Template:Lang-la) is a far northern constellation that is circumpolar for many northern hemisphere observers. It is one of the 88 modern constellations, and is also one of the 48 constellations listed by Ptolemy.

Notable features

The star Thuban (α Draconis) was the northern pole star around 2700 BC, during the time of the ancient Egyptians. Due to the effects of precession, it will once again be the pole star around the year 21,000 AD.

Although Thuban's Bayer designation is α Draconis, it is not the brightest star in the constellation. At magnitude 3.65, it is more than a magnitude fainter than the brightest star, γ Draconis (Eltanin), whose magnitude is 2.23.

There are several double stars of interest in Draco. ν Draconis (Kuma) consists of two components of magnitude 4.9, 62 arcseconds apart. They can be split with binoculars.

R Draconis and T Draconis are Mira-type variable stars. R ranges between magnitudes 6.7 and 13 with a period of 245.5 days, and T ranges between magnitudes 7.2 and 13.5 with a period of 421.2 days.

σ Draconis is relatively close to Earth, only 18.8 light years away.

The north pole of the ecliptic lies within the constellation Draco. This point is very close to the galaxy NGC 6552 and within 10 arcminutes of the Cat's Eye Nebula - NGC 6543

Notable deep sky objects

One of the deep-sky objects in Draco is the Cat's Eye Nebula (NGC 6543), a planetary nebula that is said to look like a blue disc. There are several faint galaxies in Draco, one of which is the lenticular galaxy NGC 5866, sometimes considered to be Messier Object 102.

Mythology

There are a number of myths behind the constellation Draco, due to its resemblance to a dragon [1], although alternative interpretations exist, such as the legend of the Mother Camels.

In the most famous of the myths, Draco represents Ladon, the hundred-headed dragon that guarded the golden apples of the Hesperides. The eleventh of The Twelve Labours of Heracles was to steal the golden apples. Heracles killed Ladon with a poisoned arrow, allowing him to freely take the golden apples. According to the legend, Hera later placed the dragon in the sky as the constellation Draco. Due to its position and nearby constellations in the zodiac sign of Libra (i.e. Ursa Major, Ursa Minor, and Boötes), the group of constellations can be seen to tell the tale of the eleventh labour.

In another legend, Draco represents the dragon killed by Cadmus before founding the city of thebes. In a third legend, it represents the dragon that guarded the Golden Fleece and was killed by Jason. The fact that the stars of this circumpolar constellation never set plays an important part in its mythologies.

See also

• List of stars in Draco

External links

• The Deep Photographic Guide to the Constellations: Draco
• WIKISKY.ORG: Draco constellation