Tuesday, December 15, 2009

The Ellensburg sky for the week of 12/19/09

Saturday: Have you ever looked down on the ground and spotted a penny? In Yakima? While you were standing in Ellensburg? If you have, then you may be able to see the star Hamal as more than just a point of light. It has an angular diameter that can be detected from Earth. Hamal, the brightest star in the constellation Aries the ram, has the same angular diameter as a penny 37 miles away. (For comparison, the moon is about half the diameter of a penny held at arm’s length.) Hamal is six and a half fists held upright and at arm’s length above due south at 8 p.m.

Sunday: For the next two nights, Neptune and Jupiter will be as close together in the night sky as they have been in many years. Neptune will be about a half a degree to the upper right of Jupiter. This is the diameter of the full Moon. You can prove that to yourself tonight because the Moon, a crescent moon is less than a fist to the right of the two planets. At 6 p.m., the two planets are two fists above the southwest horizon. You’ll need binoculars to see Neptune. If you are having a difficult time finding Neptune because of the stray moonlight, wait a few nights. Jupiter and Neptune will be neighbors for a few more weeks so there is no hurry to see them together.

Monday: At 11:47 a.m., the Sun reaches its lowest point in the sky with respect to the background stars. This point is called the Winter Solstice. During the day that the Sun reaches this point, your noon time shadow is longer than any other day of the year. Also, the Sun spends less time in the sky on the day of the Winter Solstice than any other day making this the shortest day of the year. Even though it is the shortest day of the year, it is not the day with the latest sunrise or the earliest sunset. The latest sunrise is during the first week in January and the earliest sunset is during the second week in December. The Sun is at its southernmost point with respect to the background stars on the day of the winter solstice. This means the Sun spends the least amount of time above the horizon on that day. But, the Sun rise and set time depends on more than its apparent vertical motion. It also depends on where the Sun is on the analemma, that skinny figure-8 you see on globes and world maps. During the second week in December, the Sun is not quite to the bottom of the analemma. But, it is on the first part of the analemma to go below the horizon. During the first week in January, it is on the last part of the analemma to rise above the horizon. For more information on this, go to http://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/dark-days.

Tuesday: Mars is two fists above the east horizon at 10 p.m.

Wednesday: Tonight’s first quarter moon is in the constellation Pisces the fish.

Thursday: What would that special someone want to see on the back of Santa’s sleigh when she gets up early Christmas morning to eat one of Santa’s cookies? A tool box? No. A circular saw? No. A subscription to The Daily Record? No. Well, maybe. But what she really wants is a ring. And if she looks out a south-facing window, she’ll see her ring. Saturn, the ringed planet, that is. Saturn is four fists above due south at 6 a.m.

Friday: Where is the one who has been born King of the Jews? We saw Jupiter being eclipsed by the Moon in the east and have come to worship him” (Matthew 2:2, Bruce Palmquist version). In 1991, astronomer Michael Molnar bought an ancient Roman Empire coin that depicted a ram looking back at a star. Aries the ram was a symbol for Judea, the birthplace of Jesus. The Magi, or “wise men”, who visited the baby Jesus practiced astrology and would have been looking in that region of the sky for the king prophesied in the Old Testament. Molnar, a modern day wise man, used sky simulation software to model the positions of planets and the Moon in the region of Aries. According to his model, Jupiter was eclipsed, or blocked, by the Moon on the morning of April 17, 6 BC. Molnar’s theory is supported by a book written by the astrologer of Constantine the Great in 334 AD. The book describes an eclipse of Jupiter in Aries and notes a man of divine nature born during this time. See http://www.eclipse.net/~molnar/ for more information.
Aries and Jupiter make an appearance in the Christmas sky tonight. At 6 p.m., the dim constellation Aries is about five fists above the east-southeast horizon and Jupiter is two fists above the southwest horizon.

The positional information in this column about stars and planets is typically accurate for the entire week.

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