This is the Griffith Observatory Sky Report for the week ending Wednesday, July 9, 2014. Here is what’s happening in the skies of southern California:
The moon becomes more obvious night by night as its phase waxes from crescent to gibbous this week, becoming first quarter on the 5th. This week, the moon remains in the sky more than 30 minutes longer after sunset each night. As a result, moonset changes from 11:19 p.m. on the 2nd to 3:08 a.m. on the 9th.
The red hue of the planet Mars, in Virgo the Maiden, contrasts with the blue tint of Virgo’s brightest star, Spica. The two are separated by only 5 degrees and appear together in the south during evening twilight. A large telescope, high magnification, and steady air are all necessary in order to see details on the planet, currently 9 arcseconds wide and shrinking as the increasing gulf between earth and Mars grows to one astronomical unit–the average distance between earth and sun–on the 3rd. The first quarter moon will appear one degree below Mars on the 5th. At the same time, the moon will block (or occult) the planet as seen from Mexico and central America.
Saturn, in Libra the Scales, appears as a bright golden star, and is located 30 degrees to the left of Mars. Saturn crosses the meridian and is due south as darkness falls. The planet and its spectacular ring system are featured through Griffith Observatory’s public telescopes.
The brightest planet, Venus, rises in the east-northeast at dawn. Venus is 17 degrees high at sunrise, when it can still be glimpsed. Starting on the 3rd, look above the horizon and the lower left of Venus to see the planet Mercury. The best time to do this is 30 minutes before sunrise, at about 5:15 a.m. Binoculars will aid you in finding Mercury against the dawn’s early light.
The largest objects of the main asteroid belt between Mars and Jupiter–dwarf planet Ceres and asteroid Vesta–are closest together in the sky on the night of the 4th. Both are easily visible in telescopes and will appear only 10 arcminutes (one third the apparent diameter of the moon) from each other in Virgo the Maiden. This will allow both objects to be seen together at magnifications of up to 150 power. Sky and Telescope Magazine has an article (with accompanying charts) that should help you to visually identify the objects through a telescope. Vesta and Ceres meet in conjunction only once every 17 years. NASA’s Dawn spacecraft is currently coasting from Vesta to Ceres, and will enter into orbit around Ceres in about six months.
Dwarf planet Pluto reaches opposition in Sagittarius the Archer at about the same time that it transits in the south on the night of July 3-4. Pluto is then at its closest point to us this year, 2.94 billion miles, a distance that light takes 4 hours and 24 minutes to traverse. Pluto is magnitude 14.1–nearly 1600 times fainter than what can be seen with the unaided sky–and is in a telescopic field filled with faint stars, making identification very difficult, even by experienced observers. A telescope of 12-inches or greater aperture and a detailed map showing stars at least as faint as Pluto is required to successfully see it. The Sky Live Pluto Tracker is an automatically updated map (with coordinates) that should be useful in this endeavor. The first close-up views of Pluto should be received a year from now (on July 14, 2015), when NASA’s New Horizons spacecraft speeds past the dwarf planet and its five known moons at close range.
Earth is at aphelion-its farthest point of our elliptical orbit from the sun-on July 3 at 5:14 p.m., PDT. At that time, the center of our planet will be 94,506,460 miles from the sun’s center. This is 1,550,653 miles farther than the average distance, and 3,099,787 miles farther than we were on January 4, when earth was at perihelion.
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 our 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, July 5.
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From Griffith Observatory, I’m Anthony Cook and I can be reached at email@example.com.