SKYLIGHTS

Astronomy news for the week starting Friday, December 22, 2000.

The Moon wanes through its crescent phase early in the week, passing new on Monday, the 25th, Christmas day. By the night of Tuesday, the 26th, Boxing Day in Canada in the UK, it will be just visible as a waxing crescent in the southwest shortly after sundown. Two days later it passes its apogee, its farthest point from Earth.

Venus, in the far southwest, grows ever more lustrous, while Jupiter, on the other side of the sky, to the east, climbs yet higher in early evening, Saturn up and to the right. Venus will pass 1.3 degrees north of Uranus the night of Saturday, the 23rd. The event will be visible in binoculars and will provide a convenient way of finding the dim planet, the seventh out from the Sun. Mercury makes less-visible news as it passes superior conjunction with the Sun (on the other side of the Sun) also on Christmas Day, just two hours after new Moon.

Overwhelming all, however, is a partial eclipse of the Sun that will be visible on Christmas Day, Monday the 25th, throughout North America. Usually, the new Moon passes above or below the Sun; this time new Moon occurs while the Moon is near crossing the ecliptic (the solar path), so it will pass across the solar disk. The event is actually a polar partial eclipse, but with the Earth's northern axis now turned away from the Sun, it centers over northern Canada. Nowhere will it be total. Time of occurrence depends mostly on time zone and longitude. In the central US, it will begin around 9:45 AM (CST), be at maximum around 11:15, and end about 12:50 PM. In the New York City area, the times are 11:10 AM (EST), 12:45 and 2:20 PM, while near San Francisco they are 7:35 AM (PST), 8:20 AM, and 9:15 AM. The coverage of the Sun by the Moon depends more on latitude: the farther north of the central US, the better the event. Chicago and New York see 55 percent. The west coast does not fare so well, however, with only 19 percent coverage in San Francisco. Please do NOT try to see the eclipse directly, as any exposure of the eye to brilliant sunlight can cause retinal burns and permanent damage. Instead, simply make a pinhole in a piece of cardboard and PROJECT the image onto a piece of paper. (Do NOT look through the pinhole!) Such pinhole projection produces a beautiful -- and safe -- optical image. You can also merely stand under a leafed tree (admittedly hard to find in winter), and see the eclipse projected on the ground through the pinhole spaces between the leaves (or pine needles).

The constellations of the zodiac this time of year brighten from southwest to northeast, from dim Capricornus (through which Venus is now sweeping), Aquarius, and Pisces, to the brighter flat triangle that makes Aries, and into Taurus (which now holds Jupiter and Saturn) and finally Gemini, the most northerly of them and the container of the Summer Solstice. Take heart, the Sun will be there in less than six months. A good holiday season to all.