At dusk in June, two planets clearly outshine all the stars. Venus, at magnitude -4 in the west-northwest, sets about 2.5 hours after sunset. Jupiter, near magnitude -2.4 in the southeast to south at dusk, reaches its highest point in the south about three hours after sunset on June 1, moving to one hour after sunset at month’s end.
Mercury passes superior conjunction on the far side of the sun on June 5. Near the perihelion of its orbit, it emerges very swiftly into the evening sky. Using binoculars, look very low in the west-northwest twilight glow, to the lower right of Venus, by 25 degrees on June 16; 20 degrees on June 25; and 17 degrees on June 30.
Later in the evening, Saturn rises within two hours after sunset on June 1, moving to around sunset on June 24, three days before opposition. Mars rises within four hours of sunset on the 1st, moving to about two hours after on the 30th. Find the Summer Triangle in the eastern sky at dusk as the season begins.
During June mornings:Jupiter on June 1 sets in the west-southwest nearly 1.3 hours before sunrise, and then 4 minutes earlier each morning. If your predawn walk occurs after Jupiter sets, you’ll see a sky dominated by Mars, in the south to south-southwest, while brightening nearly a magnitude, from -1.2 to -2.1. Saturn, near magnitude 0, is lower in the southwest, 28 to 34 degrees west of Mars. Prominent stars include the Summer Triangle, passing west of overhead; Fomalhaut in the southeast to south; Capella rising from the northeast; and Aldebaran emerging late in the month in the east-northeast.
This month features bright visible outer planets! On the morning of June 1, Spaceship Earth is heading toward constellation Aquarius, about 35 degrees to the east (left) of Mars. As our planet follows its nearly circular orbit around the sun, we overtake all three bright outer planets within 79 days, the shortest interval until 2078.
The asteroid Vesta> was the fourth to be discovered, in 1807. This month provides chances to see this asteroid with binoculars—and even the unaided eye in very dark skies. Begin with this finder chart which shows seven of the eight stars of the Teapot of Sagittarius. On the night of June 4, a line 5.7 degrees long, from 2.8-magnitude Lambda Sgr (Kaus Borealis, atop the Teapot’s lid) to 3.9-magnitude Polis (Mu Sgr), extended three degrees past Polis, ends near Vesta, magnitude 5.7. Vesta is retrograding in June, changing its place by about one-quarter of a degree daily for the rest of the month. Note the open cluster M23 within 2.5 degrees west of Vesta on June 4. On June 14, Vesta will pass closely southeast of M23. For a few days around its opposition on June 19, Vesta will reach magnitude 5.3, brighter than it will be again until July 2029.
For events at dawn, we suggest you begin viewing at least one hour before sunrise. For events at dusk, look one hour after sunset except when noted.
June 1 at dawn: The moon, nearly three days past full, is in the south-southwest at dawn, 5 degrees east (to the upper left) of Saturn and 23 degrees west (to the lower right) of Mars. Evening: Try to spot Saturn rising before Venus sets. Both are 4 degrees above opposite horizons about 2.2 hours after sunset. Three hours after sunset: The moon, just risen in the east-southeast, is 15 degrees to the lower left of Saturn.
June 2 at dawn: The waning gibbous moon is in the south to south-southwest, with Mars 12 degrees to the left, and Saturn 17 degrees to the lower right. Four hours after sunset: The moon, very low in the east-southeast, has Mars within 3 degrees to its lower right, and Saturn 27 degrees to its upper right.
June 3 at dawn: The moon is in the south, with Mars 2-3 degrees below. Saturn is 29 degrees to the lower right of the moon.
June 6-8 at dusk: A week after forming an isosceles triangle with the “Twin” stars Pollux and Castor, Venus now passes within 5 degrees to the lower left of Pollux. Look nightly, and see Venus move!
June 7-12, before dawn: The Martian south polar cap, where spring has recently begun, is now tipped 4-5 degrees toward the sun and a favorable 15 degrees into our view from Earth. The frozen carbon-dioxide polar cap is still near its maximum extent. Using your telescope with as high of a magnification as atmospheric conditions allow, look for a large bright area near the southern edge of Mars’ reddish disk. These mornings, the prominent dark marking Syrtis Major, the first Martian feature to be recorded in early telescopic observations, will appear near the center of the Martian disk on June 7 at 1:43 a.m., and about 38 minutes later each successive morning, until 4:54 a.m. on June 12. Around these times, Mars is well-placed in our sky for telescopic observation. Catch views of Syrtis Major up to two hours away from those times, provided Mars isn’t too low, or you don’t run into daylight.
June 11 at dawn: The moon is very low in the east-northeast to east. Use binoculars to spot the Pleiades cluster 15 degrees to the left of the rising moon.
June 12, 35 minutes before sunrise: Try to find the very old, thin crescent moon, 3 percent full, less than 3 degrees up, 17 degrees north of east.
June 13: The new moon, arriving at 12:43 p.m. is not visible today, neither at dawn nor at dusk.
June 14, 30 minutes after sunset: The crescent moon, some 32 hours old and 3 percent full, is 6 degrees up the in west-northwest. The moon sighting marks the end of Ramadan. Binoculars show Mercury 8 degrees to the moon’s lower right. Venus is easy to see with the unaided eye, 20 degrees to the moon’s upper left.
June 15, 30 minutes after sunset: The 8 percent crescent moon is 18 degrees up in the west to west-northwest, with Mercury 20 degrees to its lower right. Venus is within 7 degrees to the moon’s upper left.
June 16, beginning 30 minutes after sunset: The moon, at 16 percent, is well up in west, with Venus and Mercury 8 degrees and 33 degrees to the moon’s lower right. Mercury now sets a full hour after the sun.
June 17 at dusk: Regulus, heart of Leo, is within 4 degrees to the moon’s upper left. Mercury is 24 degrees to the lower right of Venus.
June 18 at dusk: Regulus is 11 degrees to the lower right of the moon.
June 19: The moon, nearing first-quarter phase, is almost 90 degrees east of the sun in the afternoon and evening sky, and appears almost half full. In the late afternoon, view or photograph the moon through a polarizing filter, rotating it to darken the blue sky, and you’ll improve the contrast well enough to observe lunar craters in the daytime! At dusk, Mercury forms an isosceles triangle with “Twin” stars Pollux and Castor 10 degrees above the planet. As twilight deepens, binoculars and telescope show the Beehive star cluster closely south of Venus.
June 20 at dusk: Can you see Saturn rising before Mercury sets? Both are nearly 5 degrees above opposite horizons at mid-twilight, 47 minutes after sunset. That makes four planets, Mercury-Venus-Jupiter-Saturn, visible simultaneously!
June 21 at 3:07 a.m.: The sun stands directly over the Tropic of Cancer, and summer begins for Earth’s Northern Hemisphere, with the shortest night and longest day. In Palm Springs, 12:48 p.m., the sun passes only 10.4 degrees south of overhead. Set up an Earth globe outdoors with your city at the top of the sphere, and the directions matched up, and your globe will have the same orientation as the Earth in space. Its axis will point nearly to the North Star, and the sunlit portion of the globe at any time of day you look will match reality. Note the North Pole is tipped into sunlight, and the South Pole is tipped into darkness.
June 21 and 22 at dusk: Spica in Virgo appears within 7 degrees to the lower left, and then 13 degrees to the lower right, of the waxing gibbous moon. On June 22, Jupiter appears within 10 degrees to the moon’s lower left.
June 23 at dusk: Jupiter is 5 degrees to the lower right of the moon. Mercury is 20 degrees to the lower right of Venus and closing.
June 24 at dusk: Mercury passes within 5 degrees to the south (lower left) of Pollux. Jupiter is 17 degrees to the moon’s upper right. On June 24 and 25 at dusk, Venus and Jupiter are about 90 degrees apart. Watch them draw together until late September, when they’ll be within 14 degrees.
June 25 at dusk: Antares, heart of Scorpius, is 8-9 degrees to the moon’s lower right.
June 26 and 27 at dusk: Mercury forms a nearly straight line with Pollux and Castor to its right. Saturn is 11 degrees to the moon’s lower left on June 26, and 1-2 degrees to the right of the full moon on June 27.
June 28 at dawn: The moon, just past full, is in the southwest, with Saturn, a day past opposition, 3-4 degrees to the moon’s lower right. At dusk, Saturn is within 13 degrees to the upper right of the moon.
June 30 at dawn: Mars is within 8 degrees to the left of the moon. On evening of June 30, Venus, Jupiter and Saturn span 135 degrees. Can you spot Mars before Venus sets? You’ll need a good vantage point; both are 2 degrees above opposite horizons about 2 1/4 hours after sunset.
The website of the Astronomical Society of the Desert at www.astrorx.org has a listing of our evening star parties. Sawmill Trailhead, our high-altitude site (elevation 4,000 feet), will have a star party starting at dusk on Saturday, June 9.
Abrams Planetarium publishes a monthly Sky Calendar with an evening sky map. Subscriptions are $12 per year. Subscribe or view a sample issue at www.abramsplanetarium.org/skycalendar.
Wishing you clear skies!
Robert C. Victor was a staff astronomer at Abrams Planetarium at Michigan State University. He is now retired and enjoys providing sky watching opportunities for a variety of groups in the Coachella Valley. Robert D. Miller did graduate work in planetarium science and later astronomy and computer science at Michigan State University and remains active in research and public outreach in astronomy.