The month of June is named after Juno, the Roman goddess who was the wife of Zeus and queen of the gods. According to myth, Juno had the power to see through a veil of clouds that Zeus put up, so our latest mission to Jupiter was named Juno since it does much the same thing today.
June always marks the beginning of summer in the northern hemisphere. This year that will be at 6:07 a.m., June 21.
We should get much warmer nights this month, but they’ll also be shorter because of the high angle of the sun. There are many interesting highlights this month, which include good appearances of all five of the brightest planets with Saturn reaching opposition on June 27. There will also be some close conjunctions with the moon and as a nice bonus, the brightest asteroid, named Vesta, will reach opposition June 19 and be visible without optical aid.
Venus reaches its highest altitude on June 6 at 28 degrees above the horizon. It will then set around 10:30 p.m., which is about as late as it could ever set. Venus will go from 80 percent illuminated down to 70 percent this month. Venus, now in Gemini the twins, will be almost evenly spaced with Castor and Pollux on June 8 and, as it continues to travel eastward along the ecliptic, will get very close to the Beehive open star cluster in Cancer on June 20, just before summer starts.
The Beehive cluster is one of the closest open star clusters to Earth. It’s visible to the naked eye as a faint smudge about three times the width of the full moon, but knowing more about it will make it that much more interesting. It has over 1,000 stars and spans about 30 light years of the sky at a distance of 600 light years away. The Beehive cluster is related to the nearby Hyades cluster in Taurus, since they both have a common point of origin in space within our galaxy based on their age and proper motion around the galaxy. The Beehive cluster is only 600 million years old, which is quite young. Our own sun and earth are about eight times older. Fish had not even emerged in our oceans at that time. Only some primitive jellyfish existed.
Jupiter is still high and bright in our eastern evening sky. The other night at 9 p.m., I saw Venus setting at about the same height above the western horizon as Jupiter was as it was rising over the eastern horizon. That was 25 degrees. Right in the middle was a first-quarter moon. Roughly the same setup will happen again at the first-quarter moon June 20.
Jupiter is getting a little fainter and farther away now, but is still much closer and brighter than usual. It will end its retrograde loop in Libra on July 9, two months after its opposition last month on May 9. Look for all four of its bright moons with just a pair of binoculars.
Saturn will reach opposition in the constellation of Sagittarius on June 27, the same day the full moon will be only one degree above the ringed planet. That’s a very auspicious way to mark its opposition this year. Saturn’s rings are now tilted open at nearly 26 degrees, about the maximum possible from our line of sight. Since Saturn is now at its closest and brightest for the year, look for its dusky polar caps, its elusive and shadowy crepe ring near the planet, and the very narrow Encke Gap in the A ring out beyond the much wider Cassini Division. You would need a telescope.
Mars is the most dramatic planet this month. It will again more than double in brightness, from minus-1.2 to minus-2.2 magnitude. It will also get 25 percent larger because we are rapidly catching up with it in our orbits. Mars begins the month rising at midnight but ends the month rising by 10:30 p.m. Mars will slow it eastward motion and begin its retrograde motion in Capricorn on June 28, one month before its long-awaited opposition on July 29, which will be its best opposition in 15 years. Look for its beautiful golden-orange glow one constellation to the east of Saturn.
Mercury makes a brief appearance low in the west-northwestern sky half an hour after sunset starting near the middle of the month. Look for a slender waxing crescent moon to pass near Mercury on June 14, then pass near Venus the next night in Gemini.
As a bonus, the brightest asteroid, named Vesta, will reach opposition on June 19 in Sagittarius, very close to Saturn. Vesta is the second-largest asteroid after Ceres, is about half its size at 330 miles in diameter, was only the fourth one discovered, in 1807, but it is the brightest. It will be visible even without optical aid this month as it reaches 5.3 magnitude before fading a little toward the end of the month.
Vesta is fascinating because it could have become a full planet based on its geology, if it hadn’t been prevented from developing due to Jupiter’s strong gravity. Vesta has a crust, mantle and core like the earth, making it unique among the millions of asteroids that orbit between Mars and Jupiter. A huge chunk of Vesta is missing near its south pole. That happened during a massive collision about a billion years ago that almost blew it apart. That one collision ejected a half-million cubic miles of material into space and is even now the source of fully 5 percent of all of the meteorites we find on Earth.
JUNE HIGHLIGHTS
June 1: The moon passes near Saturn in Sagittarius this morning.
June 3: Mars and the moon will rise just 3 degrees apart this morning.
June 4: The Compton Gamma Ray telescope was deorbited on this day in 2000 after 10 years.
June 5: Voyager 2 reached Neptune on this day in 1989 and made numerous discoveries. The last transit of Venus occurred on this day in 2012. The next one won’t be until 2117.
June 6: Last-quarter moon is at 2:33 p.m.
June 13: New moon is at 3:44 p.m. On this day in 1983 Pioneer 10 left the solar system, crossing the heliopause at 121 a.u. from the sun, or about three times farther out than Pluto.
June 16: On this day in 1963 Valentina Tereshkova became the first woman in space and still remains the only woman to do a solo space flight. Look for the Beehive star cluster halfway between brilliant Venus and the waxing crescent moon.
June 19: Vesta is at opposition with the sun tonight in Sagittarius near Saturn.
June 20: First-quarter moon is at 6:52 a.m..
June 21: Summer starts at 6:07 a.m.
June 23: The moon and Jupiter are only four degrees apart in Libra tonight.
June 26: Charles Messier was born on this day in 1730. He was a French comet hunter who developed a catalog of 110 objects in the sky that were not comets.
June 27: Saturn will reach opposition tonight, rising at sunset and not setting until sunrise.
June 28: Full moon is at 12:54 a.m. This is also called the Strawberry or Rose Moon.
June 29: George Ellery Hale was born on this day in 1868.
June 30: On this day in 1908, a comet or asteroid exploded a few miles above Tunguska, Siberia, with the force of 20 megatons of TNT, or about 1,000 times the energy of the first atomic bomb.
Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.
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