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This is the Griffith Observatory Sky Report through August 19, 2015. Here’s what’s happening in the skies of southern California.
Astronomical conditions are nearly perfect for this year’s annual Perseid meteor shower, a traditional summertime favorite. The greatest numbers of meteors are expected during the night of Wednesday, August 12, through dawn on Thursday morning with meteors increasing in number until dawn starts. Perseid meteors can appear anywhere in the sky, but they all seem to come from the direction of Perseus the Hero, under the “W” shape of the constellation Cassiopeia the Queen. Perseus moves up and to the right from the northern horizon as the sky grows dark until it ends up more than 60 degrees high in the northeast at 5:00 a.m., when the light of dawn begins to drown out the show. How many meteors you can see depends on how dark your sky is. A trip to a National or State Park far from city lights, in the mountains or desert, can result in a rate of one or two Perseids streaking into view every minute after midnight. If you must observe from suburbs or urban conditions, where light pollution prevents the glowing band of the Milky Way from being seen, expect to see only one meteor every few minutes in the hour or two before dawn. No special equipment is needed to watch meteors. Dress warmly, lie back on a reclining chair, and center your gaze high in the sky to the north or east. Remember that looking at bright lights, even the display of a cell-phone, can desensitize your eyes to the swift streaks of meteors for up to ten minutes. Chris Crawford of the American Meteor Society has information about a smart phone app that allows you to effortlessly make valuable scientific observations as you watch! Perseids can be seen on following mornings until late in the month, but the numbers of meteors fall rapidly by a factor of two each morning after Thursday’s maximum. Griffith Park, including Griffith Observatory, is not open for meteor watching after 10:00 p.m.
The moon is new on morning of August 14, so the rising of its slender crescent on the 13th at 5:24 a.m., after dawn has started, will have no effect on observing the Perseid meteors. The moon’s waxing crescent moves into the evening sky on Saturday the 16th. The moon appears close to the constellation Virgo the Maiden’s brightest star, Spica, on the 19th. On the same night, moonset occurs at 10:24 p.m.
The innermost planet, Mercury, is visible due west and about five degrees above the horizon at 8:40 p.m., the start of nautical twilight. Remember that five degrees is about half as high as your clenched fist appears when held at arm’s length. Binoculars are a helpful aid in locating the planet.
The ringed planet, Saturn, appears bright and golden to the south as darkness falls. Saturn and it’s rings can be seen through Griffith Observatory’s public telescopes. Saturn sets before 12:30 a.m.
Free views of the sun during the day and of the moon, planets, and other celestial objects at night are available to the public in clear weather through Griffith Observatory’s telescopes from Tuesday through Sunday before 9:30 p.m. Check our website for the schedule. The next public star party on the grounds of Griffith Observatory, hosted by the Los Angeles Astronomical Society, the Sidewalk Astronomers, and the Planetary Society, will take place on Saturday, August 22.
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From Griffith Observatory, I’m Anthony Cook and I can be reached at griffithobserver@gmail.com