| The Magazine of the CALIFORNIA ACADEMY OF SCIENCES |
|
|
|
Skyguide October to December 1997 October 15 Full Moon, also referred to as the "Hunter's Moon." Other names from Native American traditions are the "Moon When Water Begins to Freeze on the Edge of the Stream" (Cheyenne), and the "Leaf Fall Moon" (San Juan), both reflective of natural events. October 19 Early morning. Occultation of the bright star Aldebaran by the waning gibbous Moon about 2 a.m. The Moon moves in front of the star, blocking it from our sight. October 21 Peak of the Orionid meteor shower, hindered by the light of a bright, waning gibbous Moon. October 26 Fall back: Most of the U.S. reverts from Daylight Time to Standard Time. Theoretically, we set our clocks back one hour at 2:00 a.m. In practice, most people adjust their clocks when they go to sleep, and they wake up the next morning an hour early anyway, out of habit. November 14 Full Moon of November was known to Algonquin as the "Beaver Moon," to the Lakota Sioux as the "Moon of the Falling Leaves," and to the Cheyenne as the "Freezing Moon". Located just south of the Pleiades star cluster in Taurus, though its brightness may wash the stars from view. November 16 Peak of the Leonid meteor shower, averaging about 15 shooting stars per hour, though this year's display will be obscured by bright moonlight. With the showerÕs parent comet returning next year, astronomers are predicting the 1998 display will be better than usual. December 7 The earliest sunset of the year for Northern mid-latitudes. While the Earth spins at a relatively constant rate, it's traveling around the Sun faster at this time of the year thanduring the summer due to its slightly eccentric orbit. As aresult the earliest sunset and latest sunrise do not coincidewith winter solstice. December 8 Occultation of Saturn by the waxing gibbous Moon at about 11:00 p.m. with the planet disappearing behind the dark, leading edge of the Moon. Unlike a star, which winks out suddenly, a planet gradually fades when it's occulted, since it has a much greater diameter than a star. December 12 Once again the Moon occults a bright object. Around 9:00 p.m., watch it move in front of the star Aldebaran. December 13 Peak of the Geminid meteor showerÐÐusually the most reliable of the year, averaging 50 shooting stars per hour. December 14 Full Moon, also called the "Long Night's Moon" and the "Cold Moon" by the Algonquin, the "Moon of the Popping Trees" by the Lakota Sioux. December 21 Winter solstice for the Northern Hemisphere at 2:05 p.m. South of the equator, it's the beginning of summer, while at the north and south poles, three months of continuous darkness or daylight, respectively, have passed. December 29 New Moon-the first sighting of the crescent Moon tomorrow evening marks the beginning of Ramadan,-the Muslim month of fasting. Mercury Having dropped back into the Sun's glow, the swiftest-moving planet isn't visible in October. It reappears in November's evening sky, but then quickly retreats, becoming visibile again in the morning skies of late December. The PlanetsMercury -- Having dropped into the Sun's glow, the swiftest-moving planet isn't visible in October. It reappears in November's evening sky, but then quickly retreats, becoming visible again in the morning skies of late December. Venus -- This brilliant world dominates the sky after sunset and forms a lovely triangle in the southwest with the crescent Moon and the planet Mars on the evening of October 5. Located near the star Antares on October 16, then 2.1 degrees from Mars on the evening of October 25. Passed by the thin crescent Moon again on November 3-4 and reaches greatest eastern elongation on November 6. Through telescopes, Venus's phase shrinks during this quarter from gibbous to crescent while its apparent diameter triples. Mars -- Visible in the southwest after sunset and setting soon after. In October, located in the vicinity of Scorpius, moving into Sagittarius in November and then into Capricornus in December. As Mars passes the star Antares on the evening of October 12, you can see how the two reddish objects could often be confused for one another, hence the star's name, which means "rival of Mars." Binocular challenge: look a half-degree (the width of the Full Moon) north-northwest of Mars for distinctly greenish Uranus on December 26. Jupiter -- Located in Capricornus almost all year long, visible in Octo ber after sunset in the east-southeast. By December, look for it in the south after sunset. Outshined among the planets only by Venus, Jupiter is very prominent and easy to spot. Saturn -- At opposition on October 10, rising at sunset and visible all night long in Pisces. By December, it's well up in the east by sunset. Saturn occupies a fairly empty part of the sky, which makes it easy to pick out.
(Times are for San Francisco, CA, and assume a flat horizon.)
Bing F. Quock is a member of the staff at the Morrison Planetarium. |
Fall 1997
|
