California Wild Winter 2003

The Magazine of the CALIFORNIA ACADEMY OF SCIENCES

Skyguide

Bing F. Quock

January - March 2003

January 2 New Moon at 12:24 p.m. However, it is too close to sunset for a visible crescent to be seen this evening. Look tomorrow night.

January 3 Usual peak of the Quadrantid meteor shower, which normally averages about 40 meteors per hour. Occurring a day after the New Moon, this shower should put on a fine display, unobscured by moonlight. Also on this date, Earth reaches perihelion, its closest approach to the Sun, at 9 a.m. pst. Some calendars list perihelion on the 4th. These are written for the Greenwich Time Zone, which is eight hours ahead of Pacific Standard Time.

January 18 Full Moon. Rising shortly after sunset against the stars of Cancer, this was named the “Holiday Moon” by the Chinese, the “Quiet Moon” by the Celts, and the “Wolf Moon” by the English in medieval times.

February 1 New Moon at 2:50 a.m. As the second New Moon after the Winter Solstice, this marks the start of the Chinese year 4701. Unlike the Muslim and Jewish calendars, which mark dates by the sighting of the first visible crescent after New Moon, the Chinese calendar uses the calculated date of the actual New Moon, which is not visible.

February 16 Full Moon in Leo, near the bright star Regulus, which forms the Lion’s heart. Known as the “Little Famine Moon” to the Choctaw, the “Raccoon Moon” to the Lakota Sioux, and the “Moon When Geese Come Home” to the Omaha.

March 2 New Moon at 6:36 p.m. Tomorrow evening, look very low in the west soon after sunset for a thin, 24-hour-old crescent.

March 18 Full Moon against the stars of Virgo. The Algonquin had many names for it, including the “Sap Moon,” the “Worm Moon,” the “Crow Moon,” and the “Crust Moon.”

March 20 Spring equinox for the Northern Hemisphere at 5:01 pm. The Sun rises due east and sets due west, and theoretically, day and night are of equal length. In the Southern Hemisphere, this marks the beginning of Autumn.

	Sunrise	Local Noon	Sunset
January 1	7:25 am PST	12:13 pm PST	5:02 am PST
February 1	7:14 am PST	12:24 pm PST	5:33 pm PST
March 1	6:41 am PST	12:22 pm PST	6:03 pm PST
April 1	5:55 am PST	12:15 pm PST	6:33 pm PST

Times are for San Francisco, CA, and are accurate to within two minutes

Mercury The fastest-moving planet may be visible just after sunset for the first few days of January, but only briefly, as it’s already retreating back into the Sun’s glare. It reappears in the predawn sky at the end of the month and during the first few days of February, but then quickly darts toward the Sun and disappears again for the rest of the season.

Venus Following its December 1 meeting with Mars and the Moon, brilliant Venus is a grand predawn sight this season, rising in early January several hours before the Sun and dominating the twilight. Sweeping from Libra through Aquarius, it slowly edges northward through the season, gradually sinking toward the glow of the morning Sun at the same time. Glance through your binoculars on March 29 to see the faint, greenish planet Uranus very close to Venus—a bit of a challenge in the glow of dawn!

Mars A predawn object, Mars seems to hang relatively motionless from one morning to the next, but as the seasonal march of constellations progresses, the Red Planet actually passes slowly through the stars of Libra, Scorpius, Sagittarius, and Capricornus. The Moon swings by on the mornings of January 27, February 24 and 25, and March 25.

Jupiter In early January, the largest planet rises around 8:00 p.m., moving slowly from the stars of Leo into those of Cancer. Through the season, it rises four minutes earlier each night, slowly creeping in “retrograde motion,” or westward against the stars. Opposition to the sun occurs on February 2, when Jupiter rises at sunset and is visible all night long. The Moon passes nearby on the evenings of January 18 and 19, February 15, and March 14.

Saturn The Ringed Planet rises before sunset and is easily visible in the east by nightfall near Zeta Tauri, a star of medium brightness which marks the tip of the lower horn of Taurus the Bull. As the season progresses, it rises earlier each night and by late March it is high overhead at sunset. Compare Saturn’s slow, plodding motion against the stars with Mars, which zips through four constellations this season. Look for the Moon near Saturn on the evenings of January 14 and 15, February 11, and March 10.

The Lunar Seas

The “Sea of Rains,” “Ocean of Storms,” “Lake of Dreams,” “Seething Bay”––these are the evocative names given to features observed on the surface of the Moon. Early skywatchers thought that many of these features were bodies of water, hence their original Latin labels, “Mare” (MAH-ray), “Oceanus,” “Lacus,” and “Sinus,” respectively. These features, collectively referred to as the “maria” (MAH-ree-uh), are now known to be smooth, flat plains of rock. However, at one time they were indeed great bodies of liquid—but made of lava instead of water. These dried flows of lunar lava are great upwellings from beneath the Moon’s crust. They are thought to be triggered by asteroid impacts and gravitational stresses caused by Earth’s tidal pull on the Moon. Many observers have imagined familiar shapes among the maria; look at the Full Moon and see if you can spot the famous “Man in the Moon,” the profile of an old woman, or the silhouettes of a rabbit, a frog, a crab, or a girl reading a book.

Bing F. Quock is Assistant Chairman of the Morrison Planetarium