LISTEN to this week’s Sky Report
This is the Griffith Observatory Sky Report through August 12, 2015. Here’s what’s happening in the skies of southern California.
The orbit of the brightest planet, Venus–inside Earth’s orbit–will take Venus almost directly between the earth and the sun on August 15. As a result of it appearing closer day by day to the sun, Venus will be lost from view in the evening sky before August 8, when it sets on the western horizon at the same time as the sun.
The second brightest planet, Jupiter, is also nearing the sun and is becoming difficult to see after sunset. Jupiter’s outer orbit will take it nearly behind the sun on August 26. Jupiter will probably be lost to view during twilight before August 1.
After Venus and Jupiter are gone, Saturn is the sole remaining evening planet. Saturn appears like a steady bright golden light in the constellation Libra the Scales and becomes visible in the south-southwest about 30 minutes after sunset. It sets about four minutes earlier each night. It slips below the horizon in the west-southwest at 1:21 a.m. on July 30 and at 12:26 a.m. on the 12th. Saturn’s beautiful rings and several of its moons are currently featured through the public telescopes at Griffith Observatory.
The moon is waxing gibbous until the morning of July 31 when it is full. This is the second full moon of July, and is called a blue moon. On following nights, the moon is waning, and rises after sunset an average of 43 minutes later night after night. On August 1, it rises at 8:51 p.m., and on August 12 it rises at 4:30 a.m. Its phase wanes from gibbous and reaches last quarter on the night of August 6. On the following mornings it is crescent until August 14 when it is new.
The moonlight dims just in time for the climax of everyone’s favorite annual summertime meteors, the Perseids. The maximum of the meteor shower on the night and early morning of August 12/13 will be the topic of the next Sky Report, but increasing numbers of Perseid meteors will appear on the mornings before the maximum as moonlight decreases and the shower gains in strength. From 4 a.m. to 5 a.m. on the morning of August 10, an observer far from light pollution could see as many as 24 meteors per hour, 40 per hour at the same time on the next morning, and more than 60 per hour on the morning of the 12th, about half as many expected at maximum, on the following morning. Only about one fifth as many meteors are likely to be visible from light-polluted Los Angeles and its suburbs, so it is worth taking a trip to a mountain or desert campsite to see the greatest number of Perseids. Griffith Park and the Observatory are not open during the hours that the meteor shower is active. Perseids are named for the constellation Perseus, the hero of the Andromeda story. Although the meteors can appear anywhere in the sky, all Perseid meteors seem to stream from Perseus, high in the northeast before dawn. The meteors are caused by dusty bits of debris of the comet Swift-Tuttle that collide with our atmosphere. The comet last passed the inner solar system in 1992 and is next expected nearby in 2126.
The International Space Station will pass over Los Angeles on the night of Saturday, August 1. The giant satellite, which will appear brighter than anything else but the moon, will cross the sky from southwest to northeast between 8:38 p.m. and 8:45 p.m., and will be overhead at 8:41 p.m. A small telescope can be used to see the solar cell arrays and other large details of the ISS.
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.
Follow the Sky Report on Twitter for updates of astronomy and space-related events.
From Griffith Observatory, I’m Anthony Cook and I can be reached at griffithobserver@gmail.com