Venus and Jupiter are both now visible after sunset. Venus is buried in deep twilight in mid-May but will become more visible as the month passes. Later in May, the planet Mercury will climb up out of the glare of sunset, to appear low in the west at dusk. In the last week of May, Jupiter, Venus and Mercury will form a spectacular planetary trio. Meanwhile, Saturn – shines noticeably bright in the May 2013 evening sky all month long. And Mars is officially in the morning sky in May 2013, but not visible, having passed behind the sun from Earth last month.
Special planetary events coming up in May 2013:
Evening planets in May
Jupiter (dusk until mid-evening). It’ll be hard to miss Jupiter blazing away in the western sky after sunset. This world ranks as the fourth-brightest celestial body after the sun, moon and the planet Venus, respectively. Venus is low in the west after sunset in May, not far from Jupiter on the sky’s dome. But Jupiter is much easier to see than Venus because, while Venus slips below the horizon soon after sunset, Jupiter stays out until about an hour after dark for the most of May.
Some people describe Jupiter’s color as cream-colored. You can glimpse one or more of Jupiter’s four largest moons with binoculars, if you hold them steadily. Try propping them on your knees, or the hood of your car. With only a modest backyard telescope, you can easily see Jupiter’s moons. In order outward from Jupiter, they are Io, Europa, Ganymede and Callisto. Watch over several nights, and you’ll see them change position as they move in their continual orbit around Jupiter.
Watch Jupiter while you can. It sets in the west at mid-evening in early May, but by the month’s end, it’ll be setting before nightfall. In June, Jupiter will disappear in the sunset glare. Earth’s faster motion in orbit will bring the sun between us and Jupiter on June 19, 2013, at which time Jupiter will officially pass out of the evening sky and into the morning sky. The planet will return to view in the east before dawn in July.
Saturn (dusk until dawn).Saturn is no match for Venus or Jupiter in brightness, but it’s still as brilliant as the brightest stars. It shines like a gentle beacon in the May 2013 nighttime sky. Earth flew between the sun and Saturn late last month (April 28), and so this month Saturn is out nearly all night, in a good place to observe. Look for Saturn in the east as darkness falls. It climbs highest up for the night at late evening, and sets in the west at or close to dawn.
Just as it did last year, Saturn is still shining relatively close to Spica, the brightest star in the constellation Virgo. You can distinguish Saturn from Spica by color. Saturn shines with a golden hue while Spica sparkles blue-white. Binoculars help to accentuate color if you have difficulty discerning the difference with the unaided eye.
Binoculars won’t reveal Saturn’s gorgeous rings, but a small telescope will. The rings are inclined by nearly 18o from edge-on in May 2013, showing us their north face. The rings will appear open most widely in October 2017, displaying a maximum inclination of 27o. As with so much in space, the appearance of Saturn’s rings from Earth is cyclical. In the year 2025, the rings will appear edge-on as seen from Earth. After that, we’ll begin to see the south side of Saturn’s rings, to increase to a maximum inclination of 27o by May 2032.
If you have access to a telescope, you can also seek Saturn’s moons. Saturn’s largest and brightest moon Titan is fairly easy to observe in a small telescope.
Saturn will remain in fine view in the evening sky until September or early October 2013.
Venus (dusk).Venus, the brightest planet is officially in the evening sky throughout May 2013. It’s low in the western twilight. When will you see it? That depends on the clarity of your night sky, and on how free your western horizon is of trees and tall buildings. This evening apparition of Venus, which is only now beginning, will be good for the Northern Hemisphere observers, and awesome for our friends in the Southern Hemisphere. It’s the brightest planet! The planet of love. How can anyone not enjoy Venus when it’s in the evening sky?
Plus Venus will do something wonderful in May. Read on.
Mercury (dusk, starting mid-May).Like Venus, Mercury is climbing upward from the glow of evening twilight in May 2013. Mercury is fainter than Venus and probably won’t become visible in the twilight sky until the second half of May, though. Then, in the last week of May, three worlds – Venus, Mercury and Jupiter – will rendezvous in the western twilight sky to create a beautiful planetary trio – a gathering of three planets that are less than 5o apart on the sky’s dome. That’s less than the width of three fingers at an arm length.
You’ll want to catch the attraction low in the western sky after sunset in the final week of May, because May 2013 will present the last planetary trio until October 2015!
As the innermost planet, Mercury comes and goes in our sky rapidly. It’ll continue its evening apparition into June 2013, though, giving you plenty of chances to spot it.
Mars (not visible in May 2013) Mars was behind the sun from Earth last month, and it is still lost in the sun’s glare as we gaze in its direction in May 2013. The Martian cycle of visibility in Earth’s sky is about two years long. That cycle will begin anew when Mars returns to the eastern sky before dawn in late June 2013.
What do we mean by visible planet? By visible planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five visible planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets are visible in our sky because their disks reflect sunlight, and these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. They tend to be bright! You can spot them, and come to know them as faithful friends, if you try.
Bottom line: In May 2013, two of the five visible planets – Jupiter and Saturn – can be found in the evening sky all month. They are beautiful and fun to watch. May’s most exciting planetary spectacle comes in the final week of the month, though, when the planets Mercury and Venus meet up with Jupiter to form a planetary trio – three planets close enough together to occupy a single binocular field! Info and charts here.