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Geminid meteor shower coming

December Night Sky
By Larry Mahon
   Agate Ridge Observatory
   The Geminid Meteor Shower this year should be an excellent one. This shower reliably produces about 120 meteors per hour for an observer in a dark sky location late on the peak night.
   This year there will be no moonlight and peak activity should come on the night of Dec. 13-14. The highest hourly rates will occur between the hours of 10 p.m. and dawn.
   The shower is active for a couple of days before and about a day after. Lying back in a sleeping bag on a lounge chair is a great way to keep warm. Don't go to sleep though.
   A meteor is a Geminid if its path comes from an origin point near Castor in the constellation of Gemini. To do an official meteor count go to: skypub.com/meteors, "Advanced Meteor Observing."
   Jupiter comes to opposition 180 degrees from the sun on Dec. 2. This means that it will rise close to sunset, cross the meridian about midnight and set as sunrise occurs.
   This is a particularly favorable opposition because its 12-year orbit brings it so close to the Earth this year.
   The planet blazes at -2.8 magnitude and is 48 1/2 arc seconds wide at the equator. Jupiter's orbit also places it nearly as far north among the constellations as it can get.
   With Jupiter this high in our sky, we will have excellent viewing of the king of the planets this month. By month's end, its brightness and size will be nearly the same, except that it rises earlier.
   It will be nearly one-third of the way towards the meridian as twilight turns to darkness. On Christmas evening, the moon joins Jupiter as it slips past only 1 1/2 degrees below it.
   With the full moon only three days before, viewing the planet, above such a bright object will be difficult.
   Saturn rises around 4 a.m. as December starts, and near 2:30 a.m. at month's end. The planet brightens slightly this month and the large tilt of its ring system, 18 to 19 degrees, continues its wonderful northern exposure to the earth.
   At the beginning of December, Venus is 5 degrees below Saturn and slightly further east an hour before sunrise. It will be 18 degrees above the horizon.
   With Venus moving closer to the horizon and Saturn moving higher each day, their separation of 13 degrees reaches nearly 40 degrees by month's end as Venus slips into the morning twilight glow.
   The sun reaches the December solstice on the 21st at 6:12 a.m. PST. This is the moment when the sun is farthest south for the year and begins its six-month return northward, marking the start of winter in the Northern Hemisphere and summer in the Southern Hemisphere. Have a merry Christmas.