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This is the Griffith Observatory Sky Report through April 18, 2018. Here’s what’s happening in the skies of southern California.
The blazing white planet Venus can’t be missed while it gleams in in the western sky. It can be seen from sunset until it slips below the horizon at about 9:15 p.m. While occasionally mistaken for an aircraft light, Venus is the brightest celestial object in the sky after the sun and moon.
The second brightest planet, Jupiter, in the constellation Libra the Scales, rises in the east-southeast at roughly the same time that Venus sets in the other side of the sky. Jupiter arcs westward and is highest in the south when it crosses the meridian at about 2:40 a.m. Binoculars will make it possible for you to spot its four largest moons, but a more powerful telescope is needed to see the patterns of clouds across Jupiter’s face. Jupiter’s distinctive orange oval storm, the Great Red Spot, will be on the side of Jupiter facing telescopes in California at 2:40 a.m. on the 13th, 15th, and 18th.
The other bright outer planets, Mars and Saturn, are best placed for viewing just before dawn. By that time, butter-yellow Jupiter will be in the southwest sky. Gold-hued Saturn, in Sagittarius the Archer, is due south, higher in the sky, and far to the left of Jupiter. Orange Mars, also in Sagittarius, is only a few degrees to the left of Saturn.
Saturn’s rings are a thrill to see with nearly any telescope capable of 30 power or greater magnification. Saturn’s largest moon, Titan, is also easy to spot in a small telescope. It appears star-like, and is never farther from Saturn than four times the widest diameter of the ring. Titan completes its orbit, moving along an elliptical path outside the rings, once every 16 days. On the 12th, Titan is roughly in line with the widest part of the rings on the east side of the planet. On following mornings, it will be found along a counter-clockwise path around the south side of the rings until it is aligned with the western side of the rings on the 20th, after which it begins to loop back over the north side of the rings.
Mars is now about 91 million miles away, and it now requires a telescope of at least six inches diameter and used with high magnification in order to see the dusky markings and hazy clouds visible across the butterscotch colored desert that covers much of the planet. It is worth spending some time to try to see them now, however, so that you will be able to appreciate how much better Mars appears in late July when it comes to within 36 million miles of the Earth.
The crescent moon is visible before sunrise through the 14th. After new moon, on the 15th, it is visible after sunset starting on the 16th. On the 17th, the moon is next to Venus.
The International Space Station should appear as bright as Venus when it passes directly over Los Angeles on the evening of Friday the 13th. The space station will cross the sky from the northwest to the southeast between 7:43 and 7:50 p.m. It will be overhead at 7:46 p.m.
Free views of the Sun during the day and of the moon and other interesting 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 free 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, April 21st.
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From Griffith Observatory, I’m Anthony Cook, and I can be reached at griffithobserver@gmail.com.