StarWatch: Moravian College Astronomy
JANUARY STAR MAP |
JANUARY 3, 1999: Pharoah's Constellation
- If you caught Steven Speilbergís "The Prince of Egypt" in movie theaters over the
Holidays, you may remember a little scene where the animated camera panned up into the
night sky to reveal the constellation of Orion, shining brightly over Egypt. Spielberg
could not have picked a more appropriate constellation to be represented in his film;
for Orion--Osiris to the Egyptians--was none other than the ruler of the kingdom of the
dead. And the Egyptians certainly had a handle on the afterlife. Witness their
astronomically aligned pyramids at Giza. There is an air shaft in the Great Pyramid
which points to Alnilam, the center and brightest of the three belt stars. These
stars make the hunter so famous. In fact, the positioning of the structures of the
necropolis complex has been suggested to represent Orion. Look for Orion and its
belt in the early evening sky. By 8 p.m. Orion is in the SE, due south by 10:30 p.m.
and in the SW by 1:00 a.m. The reality that Osiris/Orion has been identified as a
constellation for the past 5000 years indicates the importance of astronomy as a
binding force of the human experience. Orion was seen by Khufu, Caesar, da Vinci,
Galileo, and Shakespeare. It can also be seen by you! Orion in its present form
was also visible tens of thousands of years ago when Cro-Magnon "man" was "slugging"
it out with the Neanderthals. As constant as the stars... As quotable as a good
story or book... How could Speilberg go wrong with the "Prince of Egypt"?
JANUARY 10, 1999: Julian Calendar
- Happy New Year! January 14 marks the beginning of the year according to the
Julian Calendar. Instituted on January 1, 45 BC, by decree of Julius Caesar, the
new calendar resulted from discussions that Caesar had with Egyptian philosophers,
including the astronomer Sosigenes. The whole process of calendar reform began
with Caesarís introduction to Cleopatra in 48 BC. The highlight of the Julian
Calendar reform was that it finally signaled the end of the Roman lunar calendar
which had grown incredibly unwieldy. The Julian Calendar took into consideration
the fact that the year took 365-1/4 days to complete. Three out of every four
years were designated as common years containing 365 days, while years divisible
by four became leap years of 366 days. The extra day was added to the month of
February. It all seemed very neat, but there was a problem. The Julian year was
11 minutes, 14 seconds longer than the true orbital period of the Earth (Tropical Year).
This meant that seasonal markers such as the first day of winter would occur slightly
earlier each year. By 1582 the difference had grown to 10 days and action was taken
under Pope Gregory to straighten out the mess. A rectification of sorts had been
made in 325 AD. The result was our present Gregorian Calendar. Century years
divisible by 400 would now only be considered leap years. Catholic countries
adopted the reform immediately, but Protestant states lagged behind. Russia
finally acquiesced in 1917. So Jan. 14 (Gregorian) equals Jan. 1 (Julian).
So Iíll say it again. Happy New Year--Julian style!
JANUARY 17, 1999: Sirius and the Nile
- The stars of the constellation Orion and their relationship to the Egyptian god
Osiris was the focus of StarWatch for Jan. 3. Another famous luminary, Sirius, found
close to Orion also played a pivotal role in Egyptian society by regulating their
solar calendar. Sirius is now beginning to dominate our evening sky. By 9 p.m. this
week, it will be a dazzling object low in the SE. By 11:00 p.m., Sirius is due south.
If youíre missing it, check to see that itís not cloudy or youíre not packing a pair
of sunglasses. "Seriously," it outranks every star in brightness except for the sun.
You can also use those three famous belt stars of Orion as a guide. Slide downward
until you come to the Dog Star. Yes, Sirius is the nose of the Great Dog, Canis Major.
Siriusí first sighting by Egyptian priests before it disappeared in the glare of a
brightening dawn (heliacal rising) commenced the beginning of the Egyptian new year,
as well as the annual flooding of the Nile River, an event which signaled the
rejuvenation of the farming cycle which was so integral to the sustenance of every
ancient culture. By coincidence, the timing of the heliacal rising of Sirius in
antiquity occurred near summer solstice, adding an extra dimension of significance
to this annual ritual. Interestingly, the 70 day period that Sirius was invisible,
due to its close proximity to the sun, was also the amount of time it took for the
Egyptian mummification ritual. Our history and traditions are intimately tied to
the stars. On Friday, the thin crescent moon is within two degrees of Jupiter, a
very beautiful early evening sight in the SW.
JANUARY 24, 1999: Blue Moons Abound
- You may have recalled earlier in the month that the moon was full. It happened
at 9:50 p.m. on Saturday, January 2 while most of us were preparing for the first
major ice storm (bust) of the winter season. Besides it was cloudy on the 2nd, so
the actual event went unobserved. While the moon revolves around the Earth in a
period of 27-1/3 days, the Earth is also moving around the sun. This causes the
moon to take an extra 2-1/6 days to cycle back into the same phase. That means
that the period between one full moon and the next full moon averages 29-1/2 days.
Add 29-1/2 days to January 2, and the next full moon occurs this month--to be precise
on Sunday, January 31 at 11:07 a.m. EST. Simply put, January has two full moons.
If youíve ever heard of the expression "Blue Moon," January has one. It is the
second full moon of the month. They donít happen that often unless February
intervenes with its 28 days (exactly four weeks). That resets the cycle so that
the first full moon of March will occur on the 2nd (1:59 a.m., EST), and you
guessed it, another blue moon on the 31st (5:49 p.m., EST). As the expression
infers, blue moon months donít happen that often; but 1999 is an exception.
The last blue moon month occurred in July 1996, and the next wonít happen until
November 2001. For a single year to have two months with two full moons occurring
in each is even rarer--about once every 19 years. The last time it happened was in
1961, while the next time will be in 2018.
JANUARY 31, 1999: Star of Wonder
- Now is a good time to start going outdoors and searching for Venus. The goddess
of beauty has swung around the backside of the sun and is now just starting to debut
in the evening. Youíll need an unobstructed horizon and a very transparent sky.
About 15 minutes after sunset, look SW about one to two fists above the horizon.
Venus sets just after 7 p.m. so youíll have about 45 minutes to catch it. Binoculars
will certainly prove useful over the next several weeks as Venus emerges as the
dominant "star" of the evening sky. You will want to become familiar with Venusí
location, because just above Venus as the sky continues to darken, you will notice
another rather bright starlike object. Thatís Jupiter, which has been with us
since late summer, blazing first in the east, then south, and now finally giving
its swan song in the west as the sun rapidly encroaches on its position. However,
the sunís steady eastward motion towards Jupiter will be outpaced by Venus.
Gradually over the next three weeks, Venus will pull away from the sun, appearing
higher and higher in the darkening sky, and closer and closer to Jupiter. By the
evening of February 23, Venus and Jupiter will be so near to each other that they
may be mistaken for a single object by the casual observer. Their separation will
be about 1/5 of a degree, less than half of the diameter of the moon. There is an
additional importance to this rare celestial event. A much closer conjunction of
these same two planets in June of 2 BC has been heralded by some astronomers and
historians as the "star" which got the Magi on their horses (not camels) to search
for the Christ Child.