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Our Friendly Skies - January 2011

December 31, 2010|By ROD MARTIN and ANDY SMETZER

Meanwhile, Saturn is entering the evening sky.  Early in the month it rises shortly after midnight, but rises well before midnight by the end of January.  It is positioning itself as the better spring and summer planet.

Saturn is highest at dawn and appears to be getting brighter.  That is because its ring system is tilted more than anytime since 2007.  It is a good telescopic target.

Jupiter is the brightest planet this month. Binoculars will help show its four larger moons.  Jupiter will set before midnight early in the month and by 9:30 late.

Jupiter is close to Uranus early in January.  Between Jan. 2 and Jan. 5, the two planets are about one half degree apart. That's the width of the full moon.  At +5.8 magnitude, a telescope or good binoculars are needed to see the blue tint of Uranus. 

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Look for Uranus to the upper right of Jupiter. See if you can tell the difference in disc size between the planet Uranus to the upper right and a similarly bright star to Jupiter's lower right.

Three planets dominate the morning sky.  Venus outshines them all.  It is very bright at -4.5 magnitude.  That is much brighter than any nighttime object except the moon.

Below Venus early in January is Mercury.  Geometry of their paths across the sky make both very favorably placed in the eastern sky.

Greatest elongation is when an inner planet appears farthest in the sky from the sun.  Venus reaches greatest elongation on January 8 when it rises almost four hours before the sun. 

Mercury is closer to the sun, so it never is as far away from the sun in the sky as Venus.  Mercury reaches greatest elongation on Jan. 9.  It rises a little less than two hours before the sun early in the month and less than an hour by the end of January.  Mercury will be brighter than other stars, but might not seem brighter since it is so low.

The third morning planet is Saturn that is due south at sunrise, but moving into the evening sky.

Mars is too low to see this month.  Wait until next May, when it rises in the morning.

Quadrantid meteor shower

The Quadrantid meteor shower peaks during the morning of Jan. 4.  This is a very active and favorable shower this year. 

Peak activity should be between 11 p.m. and 1 a.m. on the night of January 3/4, but members of the shower should be visible several days around the peak.

Sun and moon

On Jan. 1, the sun rises at 7:32 a.m. and sets at 4:57 p.m., for 9 hours and 25 minutes of daylight.  On Jan. 31, the sun rises at 7:20 a.m. and sets at 5:29 p.m., for 10 hours and 9 minutes of daylight. 

Since Earth's orbit around the sun is elliptical instead of circular, the Earth moves at different speeds at
different times of the year.  Because of that, the latest sunrise and earliest sunset do not occur on the shortest day at the solstice in December.  The latest sunrise is actually on Jan. 5 at 7:35 a.m..  It seems
that the daylight has been increasing because we usually notice sunset more than sunrise!

Because of Earth's elliptical orbit, it is actually closer to the sun in January than any other time of the year.  That seems wrong since it's so cold, but the seasons are caused by the tilt of the earth instead of
distance from the sun.  The Earth reaches perihelion on Jan. 3 around 2 p.m.  The average distance is about 93,000,000 miles, but at perihelion the distance will be 91,407,000 miles.

The sun enters the astronomical boundaries of Capricorn from Sagittarius on Jan. 19.

The moon reaches new on Jan. 4, first quarter on Jan. 12, full on Jan. 19, and last quarter on Jan.26.  A partial solar eclipse occurs on Jan. 4, but it will not be visible from North America.

Brish Planetarium and events

The current public planetarium program is "Galileo: The Power of the Telescope."  More than 400 years ago, Galileo revolutionized astronomy and science by using a telescope to observe the sky.  Witness the history and modern uses of this scientific instrument.

Programs are Tuesdays at 7 p.m.  Admission fees are $3 for adults, $2 for students, and senior citizens with a WCPS Gold Card are admitted free!


SCHEDULE CHANGE: The March-April program "New Horizons" will be replaced by "Dark Matter." This timely program will discuss new and current ideas about this elusive matter and energy.

The planetarium is at the Central Offices of the Washington County Public Schools on Commonwealth Avenue off Frederick Street in Hagerstown. The planetarium's website is www.wcps.k12.md.us/depts_programs/planetarium/index.html.  For more information about schedules and special events, go to www.tristateastronomers.org.

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