California Wild Fall 1999

Skyguide

October - December 1999

Bing F. Quock

October 9	New Moon––Tomorrow night, look for a thin crescent Moon in the west just after sunset. The Moon will then "wax," or grow, during the next two weeks, rising an average of about 55 minutes later each night.
October 22	Peak of the Orionid meteor shower, caused by dust from Halley’s Comet, averaging 15-20 "shooting stars" per hour. But the light of a waxing gibbous Moon may wash many meteors from view.
October 24	Full Moon, known as "Hunter’s Moon."
October 31	At 2:00 a.m., most of the U.S. "falls back" from Daylight Time to Standard Time. Tired Halloween trick-or-treaters won’t get much light from tonight’s Last Quarter Moon, which doesn’t rise until after midnight.
November 7	New Moon, rising and setting with the Sun. Located in Libra, but not visible because of the Sun’s glare.
November 17	Peak of the Leonid meteor shower, averaging about 15 "shooting stars" per hour.
November 22	Full Moon, known to colonial Americans as the "Beaver Moon," the "Frosty Moon," and the "Snow Moon."
December 7	New Moon This evening is too soon to see the first crescent Moon after sunset, so Muslims must wait until December 8 to officially observe the beginning of Ramadan, the month of fasting.
December 14	Peak of the Geminid meteor shower––averaging about 50 "shooting stars" per hour. Coinciding with a waxing Crescent Moon, this year’s Geminids should put on a fine show. This display isn’t as well-known in the Northern Hemisphere as summer’s Perseid shower because of the cold weather––few people stay out late to watch for it.
December 21	Winter solstice, or beginning of winter in the Northern Hemisphere at 11:45 p.m. pst. The North Pole is tipped farthest away from the Sun. On this day, the Sun rises and sets at its southernmost points along the horizon and makes its lowest, shortest arc across the sky.
December 22	Full Moon, also known as the "Moon Before Yule." It is located directly opposite the low-moving Sun; notice how high it arcs across the sky.
December 25	Winter solstice...on Mars...in the Northern Hemisphere? Nighttime low temperatures typically dip to -190 0F––low enough for carbon dioxide to freeze.

The Planets

Mercury	This planet has been making an evening appearance since early September, but the shallow angle of its path puts it very low in the sky after sunset and it is not easily visible.When it swings to the other side of the Sun and appears in the predawn sky in late November, its path will be quite steeply inclined, making it easily visible in the southeast before sunrise (look for it just below the Moon on the morning of December 5). It dips back down into the Sun’s glow in late December. On November 15, Mercury transits the face of the Sun, and will be seen (through telescopes and with proper eye protection!) as a tiny dot moving close to the Sun’s northern edge. The last solar transit by Mercury was in 1993, and the next won’t be until 2003.
Venus	A prominent predawn object, Venus rises several hours before the Sun and reaches greatest western elongation on October 31, when its angular separation from the Sun is 47 degrees. The Moon sweeps past on the mornings of October 5, forming a striking triangle with the bright star Regulus (the heart of Leo), on November 3 and 4, and December 3, forming a triangle with the bright star Spica.
Mars	Located in the southwest after sunset, the Red Planet is prominent in the evening sky and quickly moves from the stars of Ophiuchus into those of Sagittarius, then into Capricornus and Aquarius. The Moon passes by on the evenings of October 14 and 15, November 12 and 13, and––at its closest––December 12. On December 14, look with binoculars less than a degree from Mars for a distinctly greenish "star"––actually the planet Uranus.
Jupiter	Reaching opposition on October 23, Jupiter is positioned best for viewing after sunset, rising in the east. Don’t mistake it for Saturn, which rises slightly later––and don’t miss the beautiful sight on the evening of October 24, when the Full Moon, Jupiter, and Saturn form a conspicuous triangle! The Moon again passes Jupiter on the evenings of November 20 and December 17.
Saturn	Like Jupiter, the slowest of the naked-eye planets is seen in the east after sunset, reaching opposition on November 6. All season long, Saturn lingers just below the stars of Aries and above those of Cetus the Sea Monster.

Sunrise Local Noon Sunset

October 1 7:05 a.m. PST 12:59 p.m. PDT 6:53 p.m. PDT

November 1 6:35 a.m. PST 11:53 a.m. PST 5:11 p.m. PST

December 1 7:06 a.m. PST 11:59 a.m. PST 4:51 p.m. PST

January 1 7:25 a.m. PST 12:13 p.m. PST 5:01 p.m. PST

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

Whose Millennium?

As the end of 1999 approaches, almost everyone around here is preparing for "the end of the millennium." A millennium can be any series of 1,000 contiguous years, starting any time you want. But what about "The" millennium? While many countries are planning a grand millennium celebration at the end of 1999, critics say that this is plain wrong and a concession to convenience over accuracy. There was no year "0"; we went, retrospectively, from 1 B.C. straight to 1 A.D. The first thousand years A.D. should therefore last from the beginning of the year 1 to the end of 1000 and the second from the beginning of 1001 to the end of 2000.

Meanwhile, many cultures still use calendars that are based on the phases of the Moon, so they have a completely different new year, which will begin in February, and which will be 4698. For Jews, the year 5760 will already be three and a half months underway, and to Muslims, it'll be late in the year 1420, with 1421 beginning in April.

So most of the world's population may well be wondering what all the fuss is about!

Bing F. Quock is Assistant Chairman of the Morrison Planetarium at the California Academy of Sciences.

cover fall 1999

Fall 1999

Vol. 52:4