Wednesday, September 1, 2010

Draco the Dragon

In the northern sky in summer, we come across Draco the Dragon. Draco, along with Ursa Major and Ursa Minor are CIRCUMPOLAR constellations - meaning they circle the pole star and never set throughout the year.

Draco's place in the heavens is easy to locate even if it's stars are difficult to find. Look for the coiling curve of faint stars that runs between the much brighter stars of the Big and Little Dipper. The Dragon looks more like a coiled snake and the four stars marking her head are the most pronounced. The brightest of the head stars, Eltannin, points near Vega and is the farthest point away from the Big Dipper.

Draco played a much more central role in the earliest astronomy than it does today. Even though it has few bright stars, it had one that beared many names:

Thuban - "Judge of Heaven," "High Horned One," "Proclaimer of Light," "The
Favorable Judge," "Crown of Heaven."

Why so many exalted names for a mediocre star? Because of the Earth's wobble - also called precession - Thuban was Pole Star around 2800 BC. It was the only star that didn't move and was always there to guide the ancients as the North Star does today. Egyptians built pyramids to Thuban, so that its light penetrated huge shafts at key dates and times.

Draco's brightest star is Eltannin- "Dragon's Head" (Arabic) "Isis" (Egyptian). In 3500 BC, the temple of Hathor in Greece was dedicated to Eltannin. The adjoining town was named the city of the dragon.