Constellations: Overview
| Andromeda
| Antlia
| Apus
| Aquarius
| Aquila
| Ara
| Aries
| Auriga
| Boötes
| Caelum
Camelopardalis
| Cancer
| Canes Venatici
| Canis Major
| Canis Minor
| Capricornus
| Carina
| Cassiopeia
| Centaurus
Cepheus
| Cetus
| Chamæleon
| Circinus
| Columba
| Coma Berenices
| Corona Australis
| Corona Borealis
| Corvus
Crater
| Crux
| Cygnus
| Delphinus
| Dorado
| Draco
| Equuleus
| Eridanus
| Fornax
| Gemini
| Grus
| Hercules
| Horologium
Hydra
| Hydrus
| Indus
| Lacerta
| Leo
| Leo Minor
| Lepus
| Libra
| Lupus
| Lynx
| Lyra
| Mensa
| Microscopium
| Monoceros
Musca
| Norma
| Octans
| Ophiuchus
| Orion
| Pavo
| Pegasus
| Perseus
| Phoenix
| Pictor
| Pisces
| Piscis Austrinus
Puppis
| Pyxis
| Reticulum
| Sagitta
| Sagittarius
| Scorpius
| Sculptor
| Scutum
| Serpens
| Sextans
| Taurus
Telescopium
| Triangulum
| Triangulum Australe
| Tucana
| Ursa Major
| Ursa Minor
| Vela
| Virgo
| Volans
| Vulpecula
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The dragon wing of night o'erspreads the Earth.
– Achilles – having just killed Hector, sensing impending doom as well as the approaching darkness: Act V, Scene VIII, Troilus and Cressida, by William Shakespeare
| Name: | Draco (Latin: 'dragon') |
| Genitive: | Draconis |
| Short form: | Dra |
| Area: | 1,083 sq deg |
| Co-ordinates1: | Right Ascension 17h, Declination +65° |
| Origin: | Ancient |
Draco 'the dragon' is a Northern Hemisphere constellation which you have to imagine is coiled around the North Pole; you can trace it above the constellations of Ursa Major, Boötes, Hercules, Lyra and Cygnus. It's right next to Cepheus and also shares borders with Ursa Minor and Camelopardalis. Objects of interest include the famous Cat's Eye planetary nebula, the Draco Dwarf Spheroidal galaxy (a satellite of the Milky Way) and the magnificent edge-on Spindle Galaxy.
The constellation Draco2 honours the dragon Ladon, who guarded a wedding present from Mother Earth to the goddess Hera and her husband, the great god Zeus. The gift was an apple tree which grew on Mount Atlas and bore golden fruit. One of the 12 labours of Hercules (Herakles) was to steal three of the treasured apples. The only way this could be achieved was by killing the dragon, which Hercules did by firing an arrow over a wall. Hera rewarded the faithful Ladon by placing his image in the sky, marked out with stars.
Dragons
Dragons are mythical creatures who exhale fire. They have been portrayed as friends or a fearsome foe. In the East, they are a symbol of fertility, associated with water and the heavens. Some dragons can be ridden, provided you choose a friendly one, of course. Famous dragon-riders in literature are Atreyu3 and Sparrowhawk4. Famous people other than Hercules who fought with dragons include Harry Potter5, Turin Turambar6, and St George, the Patron Saint of England.
The scientific star names are simple to understand (if you know your Greek alphabet). For example: 'alpha Draconis' means that it is the brightest star in the constellation Draco. The next brightest is designated 'beta', etc. Combined with the genitive name, this is known as the 'Bayer designation'. Some stars have proper names as well, for example, alpha Draconis is Thuban. Others are known by their catalogue number. With the constellation Draco though, things didn't quite go according to the Greek letter plan, and the brightest star is the orange giant designated gamma, Eltanin, also known as the Zenith Star.
Thuban (alpha Draconis) is the sometime 'pole star' thanks to the wobble of the Earth on its axis, which is known as precession. This is caused by the combined gravitational influences of the Sun and the Moon. When the ancient Egyptians were constructing the Great Pyramid at Giza over 46 centuries ago, they incorporated a small shaft that extended from the King's Chamber to the outside of the pyramid, pointing toward Thuban, which was the pole star of the day.
Star Table
| Star | Designation | Name or
catalogue number | Magnitude | Distance
(light years7) | Spectral classification
and/or comments |
| α Dra | alpha Dra | Thuban
(Dragon's tail) | +3.65 | 309 | White giant |
| β Dra | beta Dra | Alwaid | +2.79 | 360 | Yellow giant |
| γ Dra | gamma Dra | Eltanin | +2.23 | 148 | Orange giant |
| δ Dra | delta Dra | Altaïs | +3.07 | 100 | Yellow giant |
| ε Dra | epsilon Dra | Tyl | +3.84 | 147 | Binary star system |
| ζ Dra | zeta Dra | Aldhibah | +3.17 | 340 | Blue-white giant |
| η Dra | eta Dra | Aldhibain | +2.74 | 88 | Yellow giant |
| θ Dra | theta Dra | 13 Dra | +4.01 | 68 | Yellow-white giant |
| ι Dra | iota Dra | Edasich | +3.3 | 102 | Orange giant |
| κ Dra | kappa Dra | Ketu | +3.85 | 498 | Blue giant |
| λ Dra | lambda Dra | Gianfar | +3.82 | 334 | Red giant |
| μ Dra | mu Dra | Arrakis | +4.91 | 88 | Binary star system |
| ν Dra | nu Dra | Kuma | +4.98 | 99 | Double star system |
| ξ Dra | xi Dra | Grumium | +3.73 | 110 | Orange giant |
| σ Dra | sigma Dra | Alsafi | +4.68 | 18.8 | Orange dwarf |
| φ Dra | phi Dra | Batentaban Australis | +4.22 | 289 | White giant |
| χ Dra | chi Dra | Batentaban Borealis | +3.55 | 26 | Binary star system |
| ψ Dra | psi Dra | Dziban | +4.57 | 72 | Binary star system |
The New General Catalogue (NGC) was compiled by John Louis Emil Dreyer (the director of the Armagh Observatory from 1882 to 1916).
Cat's Eye Nebula (NGC 6543)
NGC 6543 was the first planetary nebula to be observed with a spectroscope8. Commonly known as the Cat's Eye Nebula, it has other names such as the Sunflower Nebula and the Snail Nebula. It is awesome to view; through a telescope you'll see a blue-green blob, 3,300 light years distant. There are some spectacular Hubble images - the ones taken in 1994, 1997, 2000, and 2002 can be compared to show just how rapidly the nebula is expanding.
Galaxies
There are several galaxies on view in Draco, of varying types, shapes and sizes. The Spindle Galaxy (NGC 5866) is a spectacular edge-on, which means we view it like we see the rings of Saturn, from the side. The trail surrounding the Knife Edge Galaxy (NGC 5907) was more than likely left by a smaller dwarf galaxy which was eventually absorbed by the larger spiral billions of years ago. The Tadpole Galaxy (UGC 10214) is a distorted spiral whose 'tail' is 280,000 light years long. Lenticular galaxies, (like NGC 5866), are a cross between spirals and ellipticals, with lots of stellar dust giving a 'halo' effect.
Galaxy Table
| Catalogue | Name | Type | Magnitude | Distance
(light years) | Remarks |
| NGC 4121 | PGC 38508 | Elliptical galaxy | +14.2 | Unknown | Dwarf galaxy |
| NGC 4125 | UGC 07118 | Elliptical galaxy | +9.8 | 78 million | Recent merger |
| NGC 4236 | UGC 07306 | Spiral galaxy | +9.7 | 11 million | Member of the M81 group |
| NGC 5866 | The Spindle Galaxy | Lenticular galaxy | +9.9 | 44 million | Edge-on; Possibly Messier 102 |
| NGC 5907 | Knife Edge Galaxy | Spiral galaxy | +10.4 | 40 million | Edge-on; post merger |
| UGC 10214 | The Tadpole Galaxy | Distorted spiral | +14 | 420 million | Ongoing merger |
| UGC 10822 | Draco Dwarf | Dwarf galaxy | +10.9 | 260,000 | Discovered in 1954 by Albert Wilson of Lowell Observatory |
There have been six extrasolar planetary systems found in the constellation Draco up to 2010; the first was discovered in 2001. Figures given in the table below are the length of the planet's orbital period around its parent star, which we know as a year. The mass of the extrasolar planet is compared to that of Jupiter, our Solar System's largest planet, known by astronomers as the 'Jovian scale'.
Extrasolar Planets Table
Star name or
catalogue number | Planet
catalogue number | Planet mass
(Jovian scale) | Orbital period
(Earth days) | Year of discovery | Comments |
| Iota Dra | Iota Draconis b | 8.9 | 511 | 2001 | First planet discovered orbiting a giant star |
| TrES-2 | TrES-2 b | 1.25 | 2.47 | 2006 | Hot gas giant |
| HD 167042 | HD 167042 b | 1.6 | 416 | 2007 | Low eccentricity orbit |
| 42 Dra | 42 Draconis b | 3.9 | 480 | 2009 | Gas giant/habitable zone |
| HD 139357 | HD 139357 b | 9.76 | 1,125 | 2009 | Superjovian |
| Qatar-1 | Qatar-1 b | 1.09 | 1.42 | 2010 | Hot gas giant |
| Kepler-4 | Kepler-4 b | 0.077 | 3.2 | 2010 | Hot gas giant |
| Kepler-10 | Kepler-10 b | 0.014 | 0.83 | 2011 | Rocky |
| Kepler-10 | Kepler-10 c | 0.063 | 45.3 | 2011 | 'Super Earth' |
| HAT-P-30/WASP-51 | HAT-P-30/WASP-51 b | 0.71 | 2.81 | 2011 | Hot gas giant |
| HAT-P-37 | HAT-P-37 b | 1.17 | 2.8 | 2012 | Hot gas giant |
2. The Universe / Space, Stars and Galaxies / Constellations
