This is the Griffith Observatory Sky Report for the week ending Wednesday, May 9, 2012. Here is what’s happening in the skies of Southern California:
The planet Venus is still a brilliant, eye-catching object appearing high in the west-northwest in evening twilight. This week, however, the planet drops from 37 degrees to 32 degrees above the horizon at sunset between the 2nd and the 9th. Now moving between earth and the sun on its swifter, inside orbit, Venus will pass directly between the sun and us on June 5, producing an extremely rare transit across the sun’s face–the first visible from Los Angeles since 1882 and the last until 2117! Through a telescope or through steadily held binoculars, the planet’s crescent phase is now visible.
Fading planet Mars is still the brightest object in Leo the Lion about 7 degrees to the east of Leo’s brightest star, Regulus. The orange planet now has a telescopic diameter of 9 arcseconds, making planetary details difficult to see in all but large telescopes. Mars is high in the southern sky as darkness falls.
The moon’s phase changes from waxing gibbous to full moon on the 5th. The precise time of the full moon is 8:35 p.m., P.D.T. Five minutes later, at 8:40 p.m., the moon will be at perigee, the closest point of its elliptical orbit to earth. This close timing will result in the largest full moon of the year. The centers of the earth and moon will then be 221,801 miles apart, 17,056 miles closer than average. While the news media likes to make a big deal of close full moons, you will need to be very observant to notice any difference between this full moon and any other. Bear in mind that when new moon occurs on May 20th, it will be only a little over one day past its apogee, the most distant part of its orbit from us, and as a result the moon will be too small to completely cover the sun even on the centerline of the solar eclipse that afternoon. On the 200-mile wide eclipse centerline track, the sun will appear like a blinding ring, or annulus. This eclipse is thus known as an annular eclipse, not a total eclipse.
Another ring in the sky is that belonging to the planet Saturn. Saturn is well placed for viewing for most of the night, starting in the southeast at nightfall, where it appears as a bright golden star to the upper left of Virgo the Maiden’s brightest star, Spica. Saturn is the brighter of the two objects. A telescope is needed to see the planet’s spectacular rings, which are attractively tilted 13 degrees in our direction. The moon will pass close to Saturn on Thursday, May 3.
The full moon also coincides with the maximum of this year’s eta-Aquarid meteor shower, making the meteors difficult to observe. In favorable years, Aquarids produce a meteor every three minutes from low in the southeast just before dawn. The eta-Aquarid meteor shower and October’s Orionid meteor shower are both caused by fragments shed by comet Halley, still 49 years away from its next appearance.
The first commercial cargo test mission to supply the International Space Station will likely not launch as expected on May 7, pending a review of a recent engine test of the SpaceX Falcon 9 rocket. Check for updates on www.spaceflightnow.com.
Free public viewing of the sun during the day and of the moon, planets, and other celestial objects at night, is available in clear weather five days a week (Wednesday-Sunday) through Griffith Observatory’s telescopes before 9:30 p.m. Check our website for our schedule. Weather permitting, Griffith Observatory will provide free public viewing of the solar eclipse on May 20, and the transit of Venus on June 5. The next public star party of the Los Angeles Astronomical Society and the Sidewalk Astronomers is scheduled for Saturday, May 26, on the front lawn of Griffith Observatory between 2:00 and 9:30 p.m.
From Griffith Observatory, I’m Anthony Cook, and I can be reached at firstname.lastname@example.org.