The Brightest Visible Planets in June’s Night Sky: How to See them (and When)

The bright evening planets outnumber the morning planets by a 4 to 1 ratio during June. Low in the west-northwest sky, immersed in the evening twilight is dim Mars, with a much brighter Mercury passing close by during the middle and latter part of the month. Jupiter comes to opposition on the 10th and is a prominent object all through the night. Fainter Saturn follows Jupiter across the sky, trailing behind it by about two hours. Next month it will be Saturn’s turn to come to opposition. Finally, there’s brilliant Venus into her final full month as a morning star, sitting close to the east-northeast horizon just before sunrise. 

In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm’s length measures roughly 10 degrees. Here, we present a schedule below which provides some of the best planet viewing times as well directing you as to where to look to see them.

Related: Night Sky, May 2019: What You Can See This Month [Maps]

When, Where and How to See the Planets in the 2019 Night Sky

Planet Viewing Guide

Mercury will spend June in a fairly good evening apparition for Northern Hemisphere observers. As the month begins, it will be climbing out of the evening twilight over the west-northwestern horizon. In a telescope, Mercury will exhibit an 84% illuminated phase and a disk diameter of 5.54 arc-seconds. Mercury will wane in phase and grow in disk size during the month, reaching peak observability on the evenings surrounding its greatest eastern elongation on June 23. On that day, the best time to look for it will be between 9:45 and 10:15 p.m. local time. In the last week of June, Mercury will be swinging sunward again and displaying a waning crescent phase and a 9.39 arc-second disk diameter. On June 4, the very young crescent moon will sit less than 6 degrees to the left (southeast) of Mercury. On June 18, the faster orbital motion of Mercury will carry it closely past the distant, reddish planet Mars. Mercury, the brighter of the two planets, will be positioned less than 0.3 degrees above Mars, making a nice sight in backyard telescopes.

Mercury — puts on an interesting show this month. The speedy little planet loses some luster in the first half of June, fading from magnitude -1.1 on the 1st, to 0.0 on the 15th.  But it also comes into view significantly higher above the west-northwest horizon by mid-month.  For observers around 40 degrees north, the time between sundown and Mercury-set increases during this time span from about 1 hour 10 minutes to 1 hour 45 minutes.  By mid-month this planet seems unusually prominent because it outshines nearby Mars (see “Mars” below).  Two bright stars are also nearby, Pollux and Castor, which represent the starry eyes of the Gemini twins. On June 4th, about 6 degrees to the left of Mercury will be the slender sliver of a waxing crescent moon, less than 40 hours past new phase.  By June 23rd, having left Mars behind, Mercury reaches its greatest elongation from the Sun (25 degrees) this evening.  The planet is only 39 percent illuminated at this particular greatest elongation and shines not too conspicuously at magnitude +0.5.  On June 25th, if you extend an imaginary line from Castor to Pollux, then twice the distance between these two stars will bring you to Mercury. During this final week of June, Mercury gradually fades, becoming only about half as bright by month’s end, and is ultimately lost to view. 

During June, Venus will be in the closing stages of a long and very good morning apparition. On June 1, its separation from the sun will be 20 degrees. By month end, that will shrink to 12 degrees, making it increasingly difficult to see. Venus will slightly brighten throughout June, reaching magnitude -3.85 on June 30th. At the same time, its apparent disk size will decrease slightly and its illuminated phase will drop from 93.7% to 97.7%. On June 1, the old crescent moon will move to within 6 degrees to the lower right (southwest) of Venus.

Venus — is visible this month solely because of its great brilliance (magnitude -3.9).  It currently rises an hour before the sun, but that’s reduced to just 50 minutes by month’s end.  If you look very low, near the east-northeast horizon about 30 minutes before sunrise you should be able to pick it up; scanning with binoculars will make the job easier.  On the morning of June 1st, if you make a sighting, look about 7 degrees to Venus’s right for a very thin (5 percent illuminated) waning crescent moon, just two days from new phase.

Mars will spend nearly all of June among the stars of Gemini while it slides deeper into the western evening twilight. It will remain a reasonable observing target for the first part of June, when it will set just after 11 p.m. local time. At month’s end, Mars will be setting at about 10:20 p.m. local time. The planet will exhibit an apparent disk diameter of about 3.75 arc-seconds and shine with an average magnitude +1.78 during June. On June 5, the young crescent moon will sit less than 6 degrees to the upper left (east) of Mars. On June 18, the faster orbital motion of Mercury will carry it closely past Mars, with Mercury, the brighter of the two planets, positioned less than 0.3 degrees above Mars.

Mars — has been on stage in our sky for more than 1½ years, but its reign of visibility will soon be coming to a close.  On June 5th, a crescent moon will be positioned about 6 degrees to the upper left of Mars.  Currently, the red planet sets in the west-northwest around 9:30 p.m. Mercury and Mars are within 1 degree of each other from June 16th to June 19th. On June 18th they’ll pass strikingly close to each other – within 0.3 degrees – with Mars situated directly below Mercury. Look low toward the west-northwest horizon about an hour after sundown.  Binoculars will help greatly in spotting Mars, which now shines at magnitude +1.8 and is located far across the inner solar system, some 20.9 light-minutes away. Mercury gleams more than 4 times brighter at magnitude +0.2. The innermost planet is only about 7.6 light minutes away. Also take note of the twin stars of Gemini, Pollux and Castor, lurking to the upper right of the two planets. 

During June, very bright Jupiter (visual magnitude -2.6) will be an all-night target in southern Ophiuchus, slowly moving westward in a retrograde loop that will last until August. The planet will reach opposition on June 10th, when it will be located 36 light-minutes from Earth and will exhibit a large 46 arc-second apparent disk diameter. This will also be a fine time to observe Jupiter’s four Galilean moons and the little round shadows they cast upon the planet. Double shadow events occur in late evening on June 4 and June 12. Starting after sunset on the evening of June 16, the nearly full moon will sit 4 degrees to the lower left (east) of Jupiter.

Jupiter — in southern Ophiuchus, arrives at opposition on June 10th, rising around sunset and remaining visible all night long. The grand planet reaches a peak magnitude of -2.6, and telescopes show a generously large disk.  The only problem for viewers at mid-northern latitudes is Jupiter’s southerliness (declination -22 degrees) and thus lowness in the sky. For good telescopic views of Jupiter’s cloud belts and zones, look when it’s highest in the middle of the night. At sundown on June 16th, look low toward the east-southeast horizon for the rising moon and situated prominently about 4 degrees to its upper right will be Jupiter. At around midnight, Jupiter will appear to the right of the moon and the gap between them will have widened to 6 degrees. By around 5 a.m., Jupiter is just about to set with the moon now standing 8 degrees to its upper left. Jupiter is slowly retrograding (moving westward) in southern Ophiuchus, pulling closer to the ruddy star Antares sparkling to its right. They’re separated by 13 degrees on June 1st but 8 degrees on the 30th.

Saturn will spend June as a medium-bright, yellowish object moving retrograde through eastern Sagittarius — on the eastern side of the Milky Way. In early June, the ringed planet will rise in the east at about 11:30 p.m. local time and remain visible until dawn, when it will be 23 degrees above the southern horizon. By month’s end, Saturn will rise just after sunset, making it a fine all-night target for backyard telescopes. During the month, Saturn and its rings will slightly increase in apparent size and the planet will brighten from magnitude 0.28 to 0.19. Starting late on Tuesday evening, June 18, the bright waning gibbous moon will be positioned only one degree below Saturn.

Saturn — will likely be the object that everyone with a telescope will want to look at first during the next few months.  It rises at the end of twilight by June 8th, and less than a half hour after sunset by month’s end. Like Jupiter, the ringed planet comes to opposition (opposite the sun in the sky) on July 9th, but also like Jupiter, Saturn never gets very high, especially as seen from northern states, due to its southerly declination in Sagittarius, well to the left of the famous Teapot asterism.  Even at around 2:30 a.m. local daylight time when Saturn transits the meridian due south, its altitude is less than 30 degrees as seen from mid-northern latitudes. Saturn’s rings are, of course, its leading attraction.  Even a 2-inch telescope at 20 power will show them and they are still wide-open to our line of sight, their northern face being tilted 24 degrees to our line of sight.  Then there are Saturn’s moons.  The brightest, Titan, is within reach of any telescope that shows the rings. Finally, during the overnight hours of June 18-19, watch as the waning gibbous moon interacts with Saturn.  As they rise together in the east-southeast, Saturn will be the bright yellow-white “star” shining a little over a degree to the upper left of the moon. At around midnight, Saturn will shining directly above the moon and at the break of dawn it will be positioned to the right of the moon.

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Joe Rao serves as an instructor and guest lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers’ Almanac and other publications, and he is also an on-camera meteorologist for Verizon FiOS1 News in New York’s lower Hudson Valley. Follow us on Twitter @Spacedotcom and on Facebook

Source: space.com

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