Celestial Events 
by Thomas D. Nicholson 
The Moon The four-day-old crescent 
moon of December 1 is in Capricornus 
and grows to first-quarter on December 
4. The moon is in Taurus when it is full 
on December 10, and the bright reddish 
star to its light is Aldebaran. On the 
night of the 12th, the gibbous moon is 
below the stars Castor and Pollux in 
Gemini, and on the 15th it passes above 
Regulus, in Leo. Last-quarter moon is in 
Libra on the 1 8th, located just above the 
autumnal equinox when it rises about 
midnight on the 17th. The waning cres- 
cent passes Mars on the 18th, Saturn 
and Spica on the 19th, and Jupiter on 
the 21st. It will be seen near them in the 
morning sky for several days. After new 
moon early on December 26, the cres- 
cent moon of the new cycle should show 
up in the evening sky by the night of the 
28th, when it passes near Venus. Perigee 
moon (nearest the earth) is on Decem- 
ber 10 and January 8; apogee moon 
(farthest from the earth) is on Decem- 
ber 23 and January 20. 
Stars and Planets Mars, Saturn, Spi- 
ca, and Jupiter, which rise in that order 
from midnight on, offer a spectacular 
show in the morning sky, although Jupi- 
ter’s motion to the east has stretched 
November’s triangle out quite a bit. 
Look for these objects from about 4:00 
a.m., when they should be clear of the 
horizon’s murk, until dawn wipes them 
out. Note that Jupiter has now shifted 
well to the left of Virgo’s bright star 
Spica, while Mars is moving swiftly 
toward both Saturn and Spica. Saturn, 
meantime, has pulled much closer to 
Spica, but hasn’t yet passed to its left. It 
will pass it in early January, in late 
February, and again in September 1982, 
and then not for another thirty years. 
Can you guess why? I’ll tell you about it 
in the January Natural History. Mer- 
cury, you may remember, was part of 
the Saturn, Spica, Jupiter scene last 
month, but it has stayed close to the sun 
(actually moved closer to it) while both 
have moved rapidly away from Virgo. 
On December 10, Mercury passes the 
sun, on the far side as seen from the 
earth, in the position called superior 
conjunction. The planet then enters the 
evening sky, but remains too close to the 
sun (setting very soon after sundown) to 
be seen for the rest of December and 
early January. 
December 10: Mercury, in superior 
conjunction, enters the evening sky. 
December 1 1 : With perigee moon on 
the 10th and full moon only nine hours 
later on the 1 1 th, tides should be excep- 
tionally strong today and tonight as the 
effect of perigee adds to the normally 
stronger spring tide that accompanies 
syzygy twice each month (at full and 
new moon). 
December 13-14: The normally pro- 
ductive Geminid meteor shower, one of 
the two best of the year, reaches maxi- 
mum tonight. Since the full moon oc- 
curred only two nights ago, the still 
bright waning gibbous moon will ob- 
scure all but exceptional objects. Unfor- 
tunately, the Geminids seldom produce 
bright meteors. 
December 16: Venus, moving closer 
to earth, has been brightening rapidly, 
but also showing less of its sunlit sur- 
face. The best balance occurs today, and 
Venus reaches its greatest brilliancy in 
our sky. 
December 18-21: Watch the waning 
crescent moon move past the planets in 
our morning sky, highlighting each in 
turn. The moon is nearest Mars on the 
1 8th, Saturn on the morning of the 20th, 
and Jupiter on the 21st. Look for them 
from 4:00 a.m. on, in the east. 
December 21: The sun arrives at the 
winter solstice today, and winter begins 
in the Northern Hemisphere. This is 
also the shortest day of the year, al- 
though the earliest sunset occurred on 
the 9th and the latest sunrise will be 
about January 4. 
December 21-22: The Ursid meteor 
shower (about 15 per hour) reaches 
maximum after midnight. 
December 28: Venus is just above the 
crescent moon tonight. On the 30th, the 
planet begins its retrograde (westerly) 
motion. 
January 4: Earth is at perihelion, 
nearest to the sun (about 147,102,000 
kilometers, or 91,405,000 miles, dis- 
tant). 
January 8: Saturn is in conjunction 
with Spica. 
Editor’s Note: The Celestial Events Sky 
Map in the October issue shows the 
evening constellations and stars for this 
month and gives the times for use. 
Venus is the only bright evening planet 
in December, visible low in the west- 
southwest shortly after sundown. This 
hasn’t been a good evening cycle for 
the planet, however, since it is too far 
south and its position relative to the 
sun at setting keeps it low in the sky. 
The view of Venus improves in late 
December, as its position to the sun’s 
east brings it to the northerly curving 
part of the ecliptic. The early crescent 
moon passes above Venus on the night 
of the 28th, as shown here, at about 
6:00 to 6:30 P.M. 
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