Orion, the king of winter skies
By James Robinson
PagosaSUN.com staff
Tuesday, December 23, 2008

The following sun and moon data for Dec. 25, 2008 is provided by the United States Naval Observatory.

Sunrise: 7:20 a.m.

Sunset: 4:57 p.m.

Moonrise: 6:04 a.m.

Moonset: 3:21 p.m.

Moon phase: The moon is waning crescent with 3 percent of the visible disk illuminated. The moon is new Dec. 27 at 5:23 a.m. Mountain Standard Time.

With cold temperatures and a slender crescent moon this holiday — and weather permitting — skywatchers can enjoy prime conditions for observing a number of the season’s signature stars.

By 8 p.m. Orion, the king of winter skies, will have climbed well above the southeastern horizon, and observations are best begun there, using the hunter’s belt as a starting point and landmark.

Oriented vertically in our night sky, the belt points upward toward orange Aldebaran — located about two fist-widths at arm’s length above.

Aldebaran marks the ruddy eye of Taurus the celestial bull, and the star is an orange giant fluctuating between magnitude 0.75 and 0.95.

Poised higher over Aldebaran is the tiny, dipper shaped Pleiades cluster. Shimmering like tiny diamonds shrouded in wispy clouds, the Pleiades is the brightest, most famous, and arguably prettiest star cluster in our night sky. It is popularly called the Seven Sisters after a group of mythological nymphs. Although seven primary stars — hence the name the Seven Sisters — outline the dipper shaped cluster, the Pleiades holds about 100 stars.

Going back to Orion’s belt and working downward, the hunter’s belt points almost directly at Sirius, the alpha star in Canis Major. Sirius is located about two fist widths below Orion’s belt.

Shimmering at magnitude -1.44, Sirius is the brightest star in all the heavens. When viewed low above the horizon, brilliant Sirius will dramatically flicker in a variety of different colors. The flickering is caused by Earth’s atmosphere.

Deep sky objects

For those with telescopes, cold winter nights provide the best skywatching opportunities, and two of the constellations mentioned above provides a worthy deep sky target.

In Taurus, stargazers can view the famous Crab Nebula — the remnant of a star that exploded as a supernova.

In Orion, the Orion Nebula — a giant cloud of gas and dust in which a star cluster is being born — is one of the most spectacular deep sky sights.

james@pagosasun.com

Photo courtesy NASA
NASA’s Spitzer and Hubble Space Telescopes teamed up to expose the chaos that baby stars are creating 1,500 light years away in a cosmic cloud called the Orion nebula. This striking composite indicates that four monstrously massive stars, collectively called the “Trapezium,” at the center of the cloud may be the main culprits in the Orion constellation, a familiar sight in the fall and winter night sky in the northern hemisphere.