[de] [it]

Draco


gif

Abbreviation:
Dra
English name:
Dragon
Coordinates
see Stellar data

Particulars:

General:

A quite extended constellation of the northern hemisphere. The four stars forming the dragons head (beta Dra, gamma Dra, xi Dra and nu Dra), build a conspicuous asterism called the Lozenge. Draco belongs to the few constellations which really resemble the object they were named after.
The northern boundary reaches higher than DECL=+80 degrees, the southern border streches along DECL=+50 degrees; to the east and the west it extends from RA=10h to RA=20h. It looks like Draco is encircling the Little Bear, Ursa Minor.
Long time ago, about 3500 years B.C., alpha Dra, also called Thuban (arab. meaning 'the dragon'), has been the Pole Star.

Stars and other objects

Epsilon Dra is a good double to be observed with scopes at a moderate magnification. Its companions are about 3 arc sec apart.
The binary mu Dra is a good test for a scope with an aperture of 60mm. Good optics might split that pair consisting of two F7 main sequence stars (5.83 mag and 5.80 mag).
An outstanding binary is nu Dra. The two white stars (an A6V and an A4m) have magnitudes of 4.88 and 4.87. They are a good object for binoculars.
Small scopes reveal the 8th mag blue companion of the G9IIIbCN-0.5 star omicron Dra (4.66 mag).
A good binocular may be sufficient to split the pair of psi Dra. Small scopes show a 5th mag star and a 6th mag star.
Another easy pair for small telescopes is 40-41 Dra. The two yellow stars are of 6th mag. Its coordinates are roughly RA=18h and DECL=+80 degrees.
A really impressive triple system is 39 Dra. Field glasses show a wide double; in larger scopes a third star close to the brighter one occurs.
Another attractive triple is 16-17. In binoculars two blue-white stars of 5th mag are revealed. Viewing with a telescope shows another star of 7th mag close to one of the first two.
At a magnitude of 8.8, the planetary nebula NGC 6543 is one of the brightest in the sky. It was the first planetary nebula to be observed with a spectroscope; the observers were surprised to find emission lines in the spectrum of this object. This started the controversy whether planetaries are numerous stars or, as it turned out to be, clouds of diffuse gas. A small telescope (about 70 to 80 mm aperture) shows a foggy blue-green disk; more powerful scopes are required to reveal the internal structure: a bright irregular helix. Since NGC 6543 is a circumpolar object for most observers, you can view it throughout the year. It can be found half way between delta Dra and zeta Dra (RA=18h is closely running through it).
The quasar 3C 351 lies at RA=17h, DECL=+60 deg. It has a brightness of 15.3 mag and shows a redshift of .371 in its spectrum. This yields a distance of about 7 billions (7*10^9) light-years.
From October 6th to October 10th the meteor shower of the Draconids is active; this shower is associated with the comet Giacobini-Zinner and has a sharply defined maximum on October 9th.
In the midth of January the shower January Draconids seems to be active. There are only few hints for the existence of this shower.
The Eta Draconids take place from March 22nd to April 8th. The maximum occurs between March 29th and March 31st.
Between March 13th and April 17th the meteor shower of the Tau Draconids can be observed. The maximum occurs around the end of March.
There is only little evidence for the showers of the September Eta Draconids and the Omicron Draconids . Detailed information about all meteor showers, their strength and their orbits can be found the database about meteor shower from Gary Kronk.

Mythological Background:

This constellation is associated with the dragon slain by Cadmus, the brother of Europa. The father sent Cadmus to find Europa who was kidnapped by Zeus. But though he searched for his sister everywhere he could not find her. Because his father has threatened him not to come back if he failed, he left the country and search for help at the oracle of phoebus. The spell of the oracle send him to a far away place where a terrible monster, a dragon, lived, who killed all the men Cadmus had with him. After he successfully killed that dragon, the goddess Athena instructed him to plant some of the teeth of the dragon. Surpised Cadmus obeyed the goddess and the miracle happened: Armed men grew from the soil; Cadmus, afraid of the new enemy, started to lift his armes, when these people told him not to interfere their internal fights. Immediately they start to fight each other. All but five died and these five helped Cadmus to build a new city. This city was the famaous city called Thebes.
(This story can be found in "Metamorphoses, III" by the latin poet Publius Ovidius Naso (43 BC - 17 AC).)



[Constellations] [Home]



C. Kronberg --- 97/05/28 --- smil (at) clell.de