I’m sure many of you have seen how a magician makes something or someone appear to vanish, only to make that thing or person reappear a short time later . . . usually in a completely different location. Well, that’s the kind of vanishing act that the planet Venus has just pulled off. After dominating our western evening sky during the first half of this year, the brightest planet suddenly left the scene on June 3rd, only to quickly reassert itself in the eastern morning sky. But the evening sky will not be devoid of a bright planet for too long, as Jupiter and Saturn come up over the east-southeast horizon before midnight at the start of the month and will be well placed for viewing by late evening as the month comes to a close. And before Jupiter and Saturn take the title as this summer’s planetary dynamic duo of the evening, Mercury will serve as the lone early evening planet for the first 10 days of the month, sharing the spotlight with the Gemini Twins, Pollux and Castor. Meanwhile, Mars continues to approach Earth and continues to slowly ramp-up in brilliance; the combination of its increasing luster and fiery hue call attention to it for anyone outdoors during the predawn hours.
In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm’s length measures roughly 10-degrees. Here, we present a schedule below which provides some of the best planet viewing times as well directing you as to where to look to see them.
Mercury begins the month shining at magnitude +0.1 low in the west-northwest after sunset, in the midst of an excellent evening apparition. The planet seems unusually prominent because it outshines two bright stars above it, Castor and Pollux, which represent the starry eyes of the Gemini twins. In a few more days Mercury dives back into the sun’s glare. You probably won’t see it after the 11th when it will appear only about one-third as bright as it was ten days earlier. It will pass between the Earth and sun (inferior conjunction) on June 30th.
Venus reaches inferior conjunction on June 3rd at 2 p.m. EDT, when it grazes just past the sun only 0.2° from its upper limb. This is an analog of the Transits of Venus of June 8, 2004 and June 6, 2012, but it results only in a very near miss this time. How soon after inferior conjunction can you first glimpse Venus in the dawn? On June 6th, it rises just 15 minutes before the sun as seen from latitude 40° north and is probably visible only in binoculars. Can you make out the hair-line crescent with horns extending a little more than halfway around? Vaulting out of the sunrise glow, the interval between Venus-rise and sunrise increases very rapidly. It’s about 45 minutes by June 12th and almost 2 hours by month’s end. On June 19th, look very low above the east-northeast horizon about 45 minutes before sunrise for brilliant Venus (magnitude -4.5) and the narrow sliver of a waning crescent moon less than two days from new. For a given location on Earth, Venus either disappears or reappears behind the moon with the sun below the horizon on average once every 21 years. And across parts of eastern New York and New England, Venus will be positioned behind the moon (an occultation) as they rise; Venus emerging into view from behind the moon’s dark limb some minutes later, though they will be barely above the horizon. From the Canadian Maritimes, they’re a bit higher, but Venus’s emergence comes within minutes of sunrise (use binoculars). Elsewhere in the US and Canada, Venus will be visible within a degree or two to the upper right of the moon. By month’s end, you may have noticed that the orange 1st-magnitude star Aldebaran is now emerging into view about 4½° below Venus. Binoculars in early dawn may also show that Venus is about to enter into the midst of the V-shaped Hyades star cluster.
Earth arrives at the June solstice on the 20th. The sun arrives at that point where it is farthest north of the celestial equator, at 5:44 p.m. EDT. Summer officially begins in the Northern Hemisphere and winter begins in the Southern Hemisphere.
As its distance from Earth during June decreases from 94 million to 76 million miles, will correspondingly brighten from 0 to -0.5 magnitude. As the month closes, its disk will have grown big enough for a first few surface features to be glimpsed in medium-sized telescopes at morning twilight (when Mars has climbed reasonably high). During the early morning hours of June 13th, Mars will be that very bright orange-yellow “star” hovering about 4° to the upper right of the last quarter moon.
Jupiter rises in the southeast about three hours after sunset at the beginning of June. But by month’s it’s rising less than an hour after sunset and shines through the fading twilight. Jupiter is approaching a July 14th opposition.
Saturn trails behind Jupiter by about 20 minutes. A couple of hours after they rise both planets are fairly well up in the southeast and both are crossing the southern meridian between midnight and dawn. Late on the evening of June 8th, Jupiter and Saturn team up with the waning gibbous moon. Jupiter will be 7° to the upper right of the moon, while Saturn sits less than 4° directly above the moon. The gap separating the two giant planets has widened slightly to 5°.
Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers’ Almanac and other publications in New York’s lower Hudson Valley. Follow us on Twitter @Spacedotcom and on Facebook.