SKY MAP: The sky as seen at 10 pm local time on July 1 from midnorthern latitudes.
Evening skywatchers are still enjoying the sight of at least three of the five bright naked-eye planets: Venus and Saturn in the western sky and Jupiter, low in the southeast. And if you really stay up late say after 1:30 a.m. local daylight time you can add a fourth planet, Mars, emerging from above the eastern horizon and which will become increasingly prominent during the summer and fall as it slowly approaches the Earth.
But this weekend really belongs to Venus and Saturn, both easily visible in the western sky just as darkness falls.
The two planets will put on a show on both Saturday and Sunday evenings when they will appear within 0.8-degrees of each other.
The actual moment of closest approach will occur at 09:33 Universal Time on Sunday, when they will appear to close to within 0.66-degrees of each other. How close is that? The apparent width of the Moon is equal to one-half degree, and the width of your fist held at arm's length is roughly equal to 10 degrees. Unfortunately, the two planets will be below the horizon at that hour for North America, while Europe will be in daylight. It will be around sundown for Japan and Australia, however, where a good view of the closest approach between the two planets can be seen.
The two planets will then slowly pull away from each other during the rest of July.
On Friday evening, June 29, dazzling Venus will be below and to Saturn's right. Saturday evening, Venus will appear directly underneath Saturn. Come Sunday evening (July 1), Venus will have shifted to the lower left of Saturn.
By Tuesday, July 3rd, the gap between the two planets will have widened noticeably, but now they'll be side-by-side, with Venus on the left, Saturn on the right.
Specific observing details for both planets for the coming weeks:
Venus has been a prominent evening object since January, will finally relinquish the title of "Evening Star" by the start of August, so July will be your last full month to enjoy it during convenient evening hours before it makes the transition to the morning sky.
On the 8th, Venus attains its greatest brilliancy and blazes at an eye-popping magnitude of -4.5. But compared to just a week earlier it will be noticeably lower in the sky at sundown and setting just 2 hours later. On the evening of the 12th, Venus will pass less than 2-degrees below Regulus, the brightest star in the constellation Leo; you may, however, need binoculars to see the star.
By the end of July, Venus will be setting only 45 minutes after sunset; you'll need a clear and unobstructed horizon to spot it. A few more days into August and it will finally be gone from our evening sky. It will sweep between Earth and the Sun (inferior conjunction) on Aug. 18, then, just a week later it will emerge into view as a morning object, rising in the east about 45 minutes before sunrise.
By the end of August, Venus will be rising around 5 a.m. local daylight time, ultimately becoming a brilliant predawn fixture in the eastern sky for the balance of the year. If you have a telescope or even 7-power binoculars (held steadily or mounted on a tripod) you'll see Venus will appear as a beautiful crescent phase all during July and again late in August.
Saturn begins July hovering just above and to the right of dazzling Venus, and in fact, follows Venus' plunge into the sunset fires as the month progresses.
Saturn is shining at a very respectable magnitude of +0.6, but unfortunately this pales to the brilliance of Venus. Indeed, Saturn only appears one-hundredth as bright! Currently located in the constellation of Leo, Saturn's famous ring system is now tipped about 14-degrees toward Earth and still provides a spectacular view even in small telescopes.
Made up by billions of ice and rock particles of all sizes from small debris to boulders as big as houses these rings orbit Saturn at varying speeds. There are hundreds of these rings, believed to be pieces of shattered comets, asteroids or moons that broke apart before they reached the planet. The rings are so big that they would fill most of the distance between Earth and the Moon.
Speaking of the Moon, a lovely crescent will appear to hover just below and to the left of Saturn on July 16. On the next evening it will have moved well off to the east, past Venus.
One final point: if you compare Venus and Saturn with a telescope, you'll be struck by how much more dazzling Venus appears in luster compared to the mellow yellow of Saturn.
- Online Sky Maps and More
- Sky Calendar & Moon Phases
- Astrophotography 101
Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.