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
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.