Mercury, the innermost planet, never strays far from the sun. That’s why it has a reputation for being elusive. It’s always seen in a twilight sky – never overhead at midnight. It’s said only a small percentage of Earth’s population has ever knowingly seen Mercury. For the Northern Hemisphere, Mercury’s stint as the evening “star” in June 2013 will probably be your last best chance to catch Mercury in the evening sky for the rest of the year. Luckily, the brightest planet – Venus – is up in the west after sunset right next to Mercury. Venus can help guide your eye to Mercury this month. Jupiter is up there, too, but closer to the twilight and harder to catch.
Because they are near the bright twilight, you need an unobstructed horizon, in the direction of sunset, to see the planets. Look for Jupiter as soon as possible after sunset. Look for Venus and Mercury when the sky begins to darken a bit. Some 45 minutes – or less – after the sun goes down, Venus should be blazing away near the sunset point on the horizon. With the eye alone, Mercury appears above Venus. If you have binoculars, aim them at Venus to spot Mercury all the sooner above Venus, the brilliant evening “star”. These two worlds will fit – or nearly fit – within a single binocular field of view.
Jupiter makes a line, more or less, with the other two planets. Because it’s lower in the sky, deeper in twilight, you might miss Jupiter. But if you see a third object closest to the horizon, that’s it! Jupiter will soon disappear in the twilight glare as its orbit around the sun, and ours, brings the sun between us and Jupiter.
Be sure to seek these worlds no later than 45 to 60 minutes after sunset. At mid-northern latitudes – like those in the U.S. and Europe – Venus follows the sun beneath the horizon about one and one-third hours after sundown. At temperate latitudes in the Southern Hemisphere – like in southern Australia – Venus sets about one hour after the sun.
Don’t worry if cloudy skies prevent you from seeing Mercury and Venus in early June. Jupiter will sink into the sunset glare in early June, but Mercury and Venus will be visible in the evening sky for the first couple of weeks of June 2013. Be sure to watch the waxing crescent moon join up with these worlds after the sun goes down on June 10.
Mercury will reach its greatest angular distance from the setting sun on June 12, 2013. Thereafter, Mercury will fall sunward again. Meanwhile, Venus will continue to climb upward in the western twilight. Mercury and Venus will meet up for a conjunction (north-south alignment on the sky’s dome) on June 20.
Bottom line: Be on the lookout for Mercury and Venus over June 2013, starting this evening. These planets will pop out low in the west about 45 to 60 minutes after sunset – or as evening dusk begins to give way to darkness.