Seven planets will be visible in the night sky during June, with Jupiter and Venus most prominent.
Jupiter will rise in the east-southeast around midnight local time, dominating the nearby stars of the constellation Capricornus the Goat. Jupiter is a favorite target of observers with telescopes, because its rapid rotation causes its features to change position noticeably in as little as 10 minutes. Its four largest moons — Io, Europa, Ganymede and Callisto — will be visible in binoculars or any telescope, changing positions from night to night as they patrol east and west of the planet in their orbits. Occasionally one or more of them will disappear as they pass in front of Jupiter or behind it. These moons are bright enough that you could see them without optical aid if it weren’t for Jupiter’s brilliance.
The outer planet Neptune will be a close companion for Jupiter all month, appearing a half degree to the northwest. Binoculars or a telescope will be needed to see blue-gray Neptune.
Uranus will follow Jupiter and Neptune into the sky about an hour later, appearing about 30 degrees to their left (east). By 3 a.m., the blue-green planet will be high enough for good viewing in a telescope before the morning sky begins to brighten.
As darkness falls in June, yellow Saturn will materialize more than a third of the way up the sky from the southwestern horizon. It will set shortly before 2 a.m. at the start of the month and by midnight at month’s end. To Saturn’s lower right (west) will be the bright white star Regulus in the constellation Leo the Lion. Trailing Saturn across the sky to the upper left (south) will be the bright star Spica in the constellation Virgo. Saturn’s rings will appear to narrow this month, gradually tipping toward edgewise as seen from Earth. By the time the rings are edge-on to us in September, the planet will be out of sight in the solar glare.
Venus and Mars will be a lopsided pair above the east-northeastern horizon about an hour before sunrise during June, with dazzling Venus more than 100 times brighter than its faint partner. As the month advances, Mars will gradually pass from lower left (east) of Venus to upper right of it. They will be closest on June 19. Images from the Phoenix spacecraft on Mars can be seen at http://www.nasa.gov/mission_pages/phoenix/main/index.html.
Mercury will be too low to see in the dawn sky as June begins. By midmonth it will be barely visible to the unaided eye very low in the east-northeast about a half hour before sunrise.
Viewing information and graphics for the planets are available at http://www.space.com/nightsky.
Meteor shower
The Bootid meteor shower will peak before dawn on June 27, when Earth will pass through part of the debris trail of the comet that caused the meteor shower. Meteors will appear to be coming from a point in the constellation Bootes (pronounced bo-OH-teez) the Herdsman, which is visible in the northern sky nearly all night and contains the bright orange star Arcturus. The crescent moon will set before midnight, so viewing conditions should be excellent. The International Meteor Organization provides more information at http://www.imo.net/calendar/2009#jbo.
Solstice
The sun will reach the June solstice on June 21 at 1:46 a.m. EDT (5:46 Universal Time), marking the start of summer in the Northern Hemisphere and winter in the Southern Hemisphere. Universal Time is the time on the prime meridian that passes through Greenwich, England, marking zero degrees of longitude. For the next six months in the Northern Hemisphere the days will be getting shorter.
“Solstice” is derived from two Latin words that mean “cause the sun to stand still.” This is because the summer sun climbs to a higher point in the southern sky each day until the solstice. On the day of the solstice it appears to arrive at about the same maximum height above the horizon as the day before, and in the days afterward its maximum point is lower, dropping back toward its lowest point at the winter solstice. In this sense, the sun “stands still” at the peak of its journey across the summer sky before it starts downward again toward the southern horizon.
Moon phases
The moon will be full on June 7, at third quarter on June 15, new on June 22 and at first quarter on June 29.
