StarWatch: Moravian College Astronomy
StarWatch for the greater Lehigh Valley


123    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"?
124    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!
125    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.
126    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.
127    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.
January Star Map