Draco

Between Cepheus and Ursa Major in the northern sky, we can see the sprawling constellation of Draco, the Dragon. Like Cepheus, this constellation, too, has only one moderately bright star, Gamma Draconis, or Eltamin (mag. 2.2), which marks the head of the dragon. Two other stars — Beta Draconis, or Alwaid (mag. 2.79) and Eta Draconis, or Aldhibain (mag. 2.74) —are also of the third magnitude. The other stars in the constellation are all fainter than the fourth magnitude and can be seen only if the sky is exceptionally clear and dark. Then we can make out a

snake-like shape that surrounds Ursa Minor on three sides. If we have a good pair of binoculars (a 10 x 50 will do), we may be able to see quite a few double stars which include Mu Draconis, Omicron Draconis and Psi Draconis. The star Alpha Draconis, or Thuban (mag. 3.65) was the pole star in ancient times and has moved away from the pole due to the slow wobbling of Earth's axis. Draco culminates at around 9.00 p.m. during the third week of July.

Draco

Star

Name

Magnitude

Distance (Light-years)

a

Thuban

3.65

232

P

Alwaid

2.79

267

Y

Eltamin

2.20

101

T|

Aldhibain

2.74

81

Unlike the northern sky, the region around the south celestial pole is almost devoid of bright stars or easily recognisable constellations. The constellation of Octans lies at the pole, but it is made up of mainly faint stars (mag. 6 or more) and is too faint to be visible to the naked eye. In any case, the south celestial pole is not visible from anywhere in India (as it always lies below the horizon) and so need not bother us.

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