Today:
As Orion crests across the southern skies, his bright stars demonstrate considerably differences in color. Compare, for example, the star Betelgeuse on the upper left, appearing an orangish color, while on the lower right, Rigel shines a piercing blue. The colors indicate the star’s outer temperature, with red much cooler than the very hot blue.
Friday:
About one quarter of the way up, at around 6:10 PM, you’ll find the bluish star Deneb squarely in the northwest. Deneb in the 14th-brightest star in the northern celestial hemisphere. Such a ranking is impressive considering how far away Deneb is. It’s so far away that estimates vary considerably as to it exact distance, ranging between 1,600 and 2,600 light years. Among the 16 brightest stars, the next closest is Rigel, at roughly 860 light years.
Saturday:
By 9:00 PM this evening, the “twin” stars of Gemini appear quite high in the southeast, two-thirds of the way up from the horizon, and ride very high across the southern skies. Pollux, a bit brighter and on the lower left, and Castor, on the upper right, are named for the sons of the Greek god Zeus and his mortal lover, Leda.