An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

The Dragon. A large constellation that winds around the north → celestial pole, appearing to encircle → Ursa Minor. The north → ecliptic pole also lies within Draco. Abbreviation: Dra, genitive form: Draconis.

O.Fr. dragon, from L. draco "serpent, dragon," from Gk. drakon "serpent, seafish," from drak-, strong aorist stem of derkesthai "to see clearly," perhaps literally "the one with the (deadly) glance," cf. Av. darəs- "to look," huuarə.darəsa- "having the appearance of the sun," Skt. darś- "to see, appear, look, show," dárśya- "worthy of being seen;" PIE base *derk- "to look."

Eždahâ, from Mid.Pers. aždahâg, ažidahâk, from Av. aži.dahāka- "the name of an evil king in the Iranian mythology," from aži- "serpent; dragon, monster" (Mid.Pers. až, âž, aži), cf. Skt. áhi- "snake, adder," Gk. ékhis, óphis "snake," L. anguis "snake," Arm. auj, Russ. už, Lith. angis; PIE base *ang^w(h)i- "snake, worm." The etymology of the second component, Av. dahāka-, is a matter of discussion. It is probably related to dahaka- "stinging, tormenting," from dah- "to sting, to do harm."

A dwarf elliptical galaxy that is a satellite of our Galaxy and lies at a distance of about 250,000 light-years from the Galactic center. Its diameter is only about 3,500 light-years, and its absolute magnitude -8.6, making it the least luminous galaxy known.

→ Draco; → dwarf.

The time interval between two successive passages of the Moon through its → ascending node, 27.212 220 days (27d 5h 5 m 35.8s). Draconic month is important for predicting → eclipses. Also called draconitic month, nodical month.

Draconic, adj. of dragon, → Draco, referring to a mythological dragon for the following reason. Since an eclipse occurs when the Earth, the Sun, and a node are aligned and moreover the Moon is situated near the node, it was believed that a dragon that resided in the node swallowed the Sun or the Moon. → month.

Mâh, → month.
Gowzahri, related to gowzahr, from Mid.Pers. gowzihr "a node of the lunar orbit" [gowzihr sar ("head") = ascending node, gowzihr dumb ("tail") = descending node], also the astrological dragon, from Av. gao-ciθra- "keeping in it the seed of the ox," epithet of the Moon, since according to Iranian mythology the Moon keeps the seed/sperm of bovine animals; from gao- "cow, ox, bull" (Mod.Pers. gâv, Skt. gaus-, Gk. bous "ox," Arm. kov, O.E. cu, PIE *gwou-) + ciθra- "origin, seed, lineage" (Mod.Pers. cehr "origin"). Gowzahr was loaned into Arabic astronomical texts as jawzahr.
Gerehi, adj. of gereh→ node.

Two meteor showers with radiants in the constellation → Draco. One appears early in October and the other late in June.

Draconids, from → Draco constellation + → -ids suffix denoting "descendant of, belonging to the family of."

Eždahâyiyân, from eždahâ, → Draco, + -iyân→ -ids.

The brightest star in the constellation → Draco, with a visual magnitude of V = 2.23 and color B - V +1.52. It is a cool (4000 K) → giant star of spectral Type K5 III, lying 148 → light-years. Gamma Draconis has a luminosity 600 times that of the Sun and a diameter 50 times that of the Sun. It crosses the sky near the zenith point for England, a nd this was the reason why James Bradley (1693-1762) observed γ Draconis when he was trying to detect parallax and so calculate the distance. He found that the star undergoes a yearly shift of a form quite different from that expected from parallax. In a 1728 paper, Bradley announced his discovery and explained the effect as due to the → aberration of starlight . Variant names: Etamin, Etanin; Ettanin, other designations: HR 6705, HD 164058.

From Ar. At-Tinnin (التنین) "the great serpent," the Ar. rendition of the Greek constellation → Draco.