The month of June is named after the Roman goddess Juno, who is also the goddess of marriage. June has the most hours of daylight for any month in the northern hemisphere and the fewest hours of daylight for the southern hemisphere.
This year the summer solstice is at 12:38 p.m. EDT on Sunday, June 21. This is the highest point that the sun will reach on the ecliptic for the whole year. The days will be nearly 15 1/2 hours long here in New England. They will stay that long for about a week.
The main highlight this month will be an incredible and even epic conjunction of Venus and Jupiter. This event is only the middle such occurrence in a series of three similar conjunctions that could have been the appearances of the Star of Bethlehem 2017 years ago.
These two are our brightest planets and they will be just one third of a degree apart on Tuesday evening June 30. They start the month about 25 degrees apart. Then they will stay within just two degrees of each other for eight full days.
Watch Venus all month long as it goes on an interesting journey through Gemini and Cancer before it gets to Jupiter in Leo by the end of the month. On June first, the stars Castor and Pollux are evenly spaced in a nearly straight line with Venus in Gemini. Venus will also be exactly half lit by the sun. Watch as it gets less illuminated by the sun even as it gets brighter and larger and closer to Earth.
On the 13th, another nearly straight line of equidistant objects occurs with Venus, Jupiter, and Regulus, the brightest star in Leo the lion and the 21st brightest star in the sky. On Flag Day, June 14, our sister planet will pass right through the Beehive open star cluster in Cancer the Crab. It will be less than one degree from the center of this cluster which is visible without binoculars.
Then the waxing crescent moon chimes in and forms spectacular conjunctions with the pair in a true celestial waltz of great beauty and power. All of this happens before the real highlight of Venus being less than the width of the full moon below Jupiter.
Venus will be 15 times brighter than Jupiter by this time and it will also be very close in size to the King of the planets, 33 arc seconds across. Venus is actually 10 times smaller than Jupiter, like the earth. It will look the same size in the sky from our earthly vantage point in space. Then they will both set about 2 and a half hours after sunset, so the timing is perfect to witness this rare and memorable conjunction. Try to photograph this great event as it unfolds and culminates along with some of the other interesting stops that Venus will take on its way to its close encounter with the king of the planets.
Saturn is now just past opposition, but it will still be well placed for viewing and be brighter and closer to us than usual right through this summer. The ringed planet started its retrograde or westward motion in the sky back towards Libra on March 14, which is also Einstein’s birthday and pi day. A superior planet’s opposition always occurs at the midpoint of its retrograde motion, which was May 22 this year for Saturn. It will return to its normal eastward motion on August 2.
Saturn’s globe covers 18 arc seconds of the sky and with its rings it covers 41 arc seconds, which is more than any other planet right now. Saturn’s rings are tilted wide open at 24 degrees from edgewise. Look carefully through a telescope and you will notice that its famous rings are tilted so far open that they extend just beyond its poles, thereby hiding the South Pole from view. The nearly full moon will pass just above Saturn on June 28th.
Mercury will reach its greatest western elongation from the sun on June 24. It will be 35 percent lit by the sun and getting more illuminated. Look for our first planet low in our east-northeastern sky 45 minutes before sunrise and just to the left of the orange giant star named Aldebaran, the fiery eye of Taurus the Bull. This star is 40 times the width of the sun, so if you could place it where the sun is in our sky, it would cover 20 degrees of our sky and its surface would extend almost to the orbit of Mercury, which appears to be right next to it now for a few days but is actually 65 light years away from this orange giant star whose name means “the follower.” Our first man-made deep sky probe, Pioneer 10, will reach this star in about two million years.
By the middle of June the entire summer triangle will once again be visible, having cleared the eastern horizon by 11 p.m. You know the earth has completed one more helical orbit around the sun and summer is once again poised on our doorstep, ready to burst forth in all of its glory when you see this configuration of stars at this time of night.
Through a telescope you can once again view some classic favorites in this part of our sky. These include the Ring Nebula, formed by the explosion of a star similar to our own about 7,000 years ago. This giant ring already spans 1 light year of space and will continue to expand for about another 10,000 years when it will fade out and blend into the interstellar medium. In a sense you are looking 5 billion years into the future when you view this remarkable phenomenon called a planetary nebula. You can also see Albireo, a beautiful blue and gold double star located about 400 light years away marking the head of Cygnus the Swan. Then you can see the North American nebula in Cygnus and the Veil nebula, a supernova remnant from a cataclysmic explosion that happened about 50,000 years ago.
Look just below this great triangle to see Delphinius the Dolphin. It is easy to picture a heavenly dolphin jumping for sheer joy out of the cosmic ocean when you view this faint but distinct little group of stars right below the famous summer triangle.
June 1: The nearly full moon is a few degrees above Saturn tonight.
June 2: Full moon is at 12:19 p.m. EDT. This is also called the Strawberry or Rose Moon.
June 3: A double shadow transit occurs on Jupiter tonight. The George Ellery Hale 200 inch Mt. Palomar telescope was dedicated on this day in 1948.
June 4: On this day in 2000 the Compton Gamma Ray telescope reentered our atmosphere.
June 5: On this day in 1989 Voyager 2 began observations of Neptune.
June 9: Last quarter moon is at 11:42 a.m.
June 13: The Beehive cluster glows just below Venus, which is within 10 degrees of Jupiter tonight.
June 16: New moon is at 10:05 a.m. On this day in 1963 Valentina Tereshkova became the first woman in space and still has the only solo space flight by a woman.
June 19: The waxing crescent moon passes near Venus and Jupiter this evening.
June 21: The summer solstice is today at 12:38 p.m. for the Northern Hemisphere.
June 24: First quarter moon is at 7:02 a.m.
June 26: Charles Messier was born on this day in 1730.
June 28: Saturn is about 2 degrees below the moon tonight.
June 29: George Ellery Hale was born on this day in 1868.
June 30: Venus and Jupiter are at their closest tonight, just 1/3 of a degree apart. On this day in 1908 a comet or asteroid exploded about 5 miles above Tunguska in Siberia with the force of 20 megatons, or about 1,000 times the force of the first atomic bomb we dropped over Hiroshima. The impact leveled 80 million trees over 1,000 square miles but did not leave a crater.
— Bernie Reim is an amateur astronomer and teaches astronomy lab courses at the University of Southern Maine.
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