Sky Watch: Summer Solstice to Bring More Daylight
Sunday, May 31, 2009
June has more sunlight than any other month, as the summer solstice for the Northern Hemisphere arrives June 21 at 1:46 a.m., according to the U.S. Naval Observatory. It's the first day of summer, and at that time we get the maximum amount of daylight. Washington will enjoy 14 hours and 54 minutes of daylight from June 18 to 23.
If you desire more sun, head north. Baltimore gets 14 hours and 56 minutes of daylight June 15-26, and Boston enjoys 15 hours and 17 minutes between June 18 and 23.
Washington's earliest sunrises of the year occur between June 10 and 17, when the sun climbs in the east at 5:42 a.m., according to the observatory. The latest sunsets happen June 27-28, when the sun sets at 8:38 p.m. each night.
The summer solstice is the astronomical point in time when the sun appears to touch the Tropic of Cancer. Immediately after the solstice, the sun starts its return trip toward the equator and later the Tropic of Capricorn.
Right after sundown, spot Saturn high in the southwest, still loitering with the constellation Leo the Lion. Its famous rings are almost "edge-on" to Earth, and they flatten out more throughout summer. Tomorrow night, the waxing gibbous moon is to Saturn's south. This big, gaseous planet is zero magnitude, but it will be first magnitude by month's end.
Jupiter ascends the eastern morning sky about 1:30 a.m. now, and by 4 a.m. it is easily found, at negative second magnitude (bright), high in the southeast. By the end of June, this giant planet rises in the southeast about 11:30 p.m.
Mars and Venus rise before dawn in the eastern sky, about 4 a.m. now. If you are at the beach, facing east, you should spot them low above the horizon. Of the two planets, Venus is brighter and Mars has a faint reddish tint. Mars is first magnitude (moderately bright) and Venus is negative fourth magnitude (very bright). The effervescent Venus starts June to the right of Mars, but near the solstice, Venus passes the red planet, and Mars is to the right of Venus by month's end.
To the moon: Soon NASA will launch the Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Satellite, or LCROSS.
The orbiter will examine and plot the moon's surface features. About four months from now, the launch vehicle's upper stage will crash into the lunar surface, sending a plume of moon dust and debris up six miles, for scientists to ascertain the possibility of water ice. LCROSS will pass through the plume, then crash. Space-based and land-based telescopes will observe the crashes. At the earliest, the two spacecraft will launch concurrently June 17 from Cape Canaveral. http:/
Tomorrow -- Jonathan Harmon, planetarium director, explains the "Stars Tonight" at Arlington County's David M. Brown Planetarium, 1426 N. Quincy St., adjacent to Washington-Lee High School (four blocks from Ballston Metro). $3 adults, $2 seniors and children. 7:30 p.m. 703-228-6070; http:/
Friday -- Astronomer Neil Miller lectures on "Radio Astronomy: Past, Present and Future" at the open house of the University of Maryland Observatory, College Park. See heavens afterward, weather permitting. 9 p.m. 301-405-6555; http:/
June 13 -- John Mather of the Goddard Space Flight Center provides an update on the James Webb Space Telescope, scheduled for launch in 2014, at the National Capital Astronomers meeting, University of Maryland Observatory, College Park. 7:30 p.m. http:/