Friday, June 3
• Saturn lies opposite the Sun in our sky today (officially at 3 a.m. EDT) and reaches its peak visibility for 2016. The ringed planet appears low in the southeast as darkness falls and grows more prominent as the evening wears on and it climbs higher. It stands about one-third of the way to the zenith in the southern sky around 1 a.m. local daylight time. Saturn lies among the background stars of southern Ophiuchus and shines at magnitude 0.0, nearly 10 times brighter than any of this constellation’s stars. When viewed through a telescope, the dramatic ring system spans 42" and tilts 26° to our line of sight, while Saturn’s family of moderately bright moons appears next to the gorgeous world.
• The Moon reaches perigee, the closest point in its orbit around Earth, at 6:55 a.m. EDT. It then lies 224,402 miles (361,140 kilometers) away from us.
Saturday, June 4
• Another comet in the growing crowd of such objects discovered by the Pan-STARRS telescope in Hawaii makes its appearance in June’s morning sky. Comet PANSTARRS (C/2013 X1) currently glows around 7th magnitude in southern Aquarius. As a bonus today, the comet’s head lies less than 1° east of the Helix Nebula (NGC 7293) while the comet’s tail grazes this bright planetary. From most of the United States, you’ll need a haze-free southeastern horizon to spot the comet through a telescope shortly before dawn breaks.
• New Moon occurs at 11:00 p.m. EDT. At its new phase, the Moon crosses the sky with the Sun and so remains hidden in our star’s glare.
Sunday, June 5
• Mercury reaches greatest elongation today, when it lies 24° west of the Sun and stands 6° high in the east a half-hour before sunrise. The innermost planet shines at magnitude 0.5 and shows up easily through binoculars if you have an unobstructed horizon. When viewed through a telescope, Mercury appears 8" across and about one-third lit.
Monday, June 6
• Mars remains near its peak all this week. The Red Planet reached opposition on May 22 and made its closest approach to Earth (at a distance of 46.8 million miles [75.3 million kilometers]) on the 30th. Mars appears low in the southeast as darkness falls and grows more prominent as the evening wears on and it climbs higher. By 11:30 p.m. local daylight time, it stands one-third of the way to the zenith in the southern sky against the backdrop of southeastern Libra. The world shines at magnitude –1.9, just a hair dimmer than the brightest point of light in the sky, Jupiter. When viewed through a telescope, Mars’ orange-red disk spans 18.5". Look for subtle dark markings along with a whitish north polar cap.
• Venus passes behind the Sun from our perspective, a configuration astronomers call superior conjunction, at 6 p.m. EDT. (Our star actually occults the planet, an event that last occurred eight years ago.) Needless to say, the Sun’s glare makes it impossible to see Venus. The planet will return to view after sunset in late July.