Night Lights: 20 bright lights of night

Graphic courtesy of Andy Veh.

Graphic courtesy of Andy Veh.

By Andy Veh, for the Redoubt Reporter

The winter constellations are rising in the east and gaining altitude throughout the next two months. Orion is easy to spot with its seven bright stars — among them, red Betelgeuse is the 10th-brightest star we see from Earth, and blue Rigel is the seventh-brightest — and its stellar nursery, the Orion Nebula. Also look for Taurus with red Aldebaran (14th-brightest) and its prominent star cluster, the Pleiades; Auriga with yellow Capella (sixth-brightest); and Gemini with the twin stars Castor (23rd-brightest) and Pollux (17th brightest).

The head of Canis Major has the brightest star (aside from the sun) that we can see from Earth — Sirius, as well as Procyon (eighth-brightest). Look for Regulus (21th-brightest) in Leo very late in the evening.

Because this region of the sky hosts seven of the 20 brightest stars (again, not counting our sun) as seen from Earth, and because it contains quite a few easily recognizable constellations, it is my favorite region of the sky.

High in the south is the Great Square of Pegasus in the shape of a diamond. Above it, close to the zenith, is Cassiopeia. Getting close to the western horizon — but never completely setting in Alaska — are the three stars that make up the summer triangle, Deneb (20th-brightest) in Cygnus, Vega (fifth-brightest) in Lyra, and Altair (13th-brightest) in Aquila. Aquila does set, but just barely for a few hours.

In the north are Ursa Major’s Big Dipper and Ursa Minor’s Little Dipper, which is always close to 60 degrees, our latitude on the Kenai.

Keep looking for Neptune and Uranus in the evening. They appear quite low now in the south in Aquarius and Pisces (both are below Pegasus). A good finder chart is needed, though. Try here. The first-quarter moon joins Neptune on Dec. 16, and then Uranus on Dec. 19. That may make it easier to find these planets, but it also makes the sky brighter around them and diminishes the contrast.

Mercury might be seen very low on the southwestern horizon at the end of the month.

Jupiter in Leo is now rising around midnight, almost exactly in the east. It and Mars remain visible for the rest of the night. The third-quarter moon joins the giant Dec. 3 and 4 and again Dec. 31. While our moon looks a lot bigger, it’s only because it’s a lot closer. Jupiter is actually 40 times larger in diameter.

Much-fainter Mars in Virgo rises around 3 a.m., with the waning crescent moon nearby Dec. 5 and 6. Leo’s Regulus, Jupiter, Mars and Virgo’s Spica (16th-brightest star) from a long baseline of a triangle with Arcturus (fourth-brightest) at the tip farther north.

Venus rises around 6 a.m. but stays low in the southeast as is nearing the sun for the remainder of winter. The waning crescent moon reaches it Dec. 7.

Saturn is too close to the sun to be seen.

The winter solstice occurs Dec. 21 when the northern hemisphere’s axis tilts the farthest away from the sun, giving us the shortest day (with the sun about five hours above the horizon) and the lowest sun in the sky at only 7 degrees above the southern horizon at noon. The low altitude and short duration of sunlight combine to give us little heat. The northern hemisphere actually experiences a net heat loss, as it radiates more heat into space than it gains from the sun.

Therefore, we have low temperatures during the months around the winter solstice. Even our closest approach to the sun in our almost-circular orbit Jan. 4 is by far not enough to alleviate the overall chill.

The Geminid meteor shower peaks Dec. 14. The meteors are impressive because they bring forth many bright and typically yellowish-white bursts. While many meteor showers are relics of a comet’s tail, this one is probably based on the asteroid Phaeton.

Andy Veh is an associate professor of physics, math and astronomy at Kenai Peninsula College.


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