Three out of five bright planets are lost to view during this month: Mercury and Mars in the evening sky and Venus in the morning sky. That only leaves Jupiter and Saturn, however, they both are in excellent position for observation in the evening sky all month long. In fact, on July 9, Saturn comes to opposition, rising in the east-southeast as the sun is going down and remaining in view all night long until daybreak the following morning. The nearly full moon has a rather close encounter with Saturn on the night of July 15-16.
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, July 2019: What You Can See This Month [Maps]
When, Where and How to See the Planets in the 2019 Night Sky
Planet Viewing Guide
During the early part of July, Mercury will be visible low in the western evening sky for a short period after sunset, the best viewing time falling between 9:30 and 10 p.m. local time. In a telescope, Mercury will exhibit a waning crescent as it slides towards inferior conjunction with the sun on July 21. During the final week of July, the swift planet will re-appear in the eastern pre-dawn sky, now showing a waxing slim crescent. For both appearances, the planet's apparent disk size will be a healthy 10 arc-seconds. On July 3, the young crescent moon will be positioned less than 3 degrees to the lower right (west) of Mars and 5.5 degrees to the right of Mercury.
Mercury — is an evening object as July begins, sitting close to a much dimmer Mars. Both are very low near the west-northwest horizon, setting within an hour after the sun. While they might be glimpsed in binoculars, but within a few days they are lost in the glare of sunset. On July 21st Mercury passes through inferior conjunction with the sun. The planet then emerges into the dawn sky, but it's still too faint to observe in morning twilight even by the end of July. At its next inferior conjunction on November 11th, Mercury will pass across the sun's face (called a "transit") as seen from the Americas, the Atlantic, Africa, Europe and western Asia.
During July, Venus will close a long apparition in the eastern morning sky and disappear from view near the sun as it heads toward solar conjunction. The planet will re-appear in the western evening sky in September.
Venus — is in the morning sky and rises about an hour before the sun as July starts, and only about a half hour before as July ends. Although the planet shines at a brilliant magnitude -3.9, it will become increasingly harder to find low in the bright east-northeast sky as the month progresses. By midmonth, it's all but gone from our view and will be too close to the sun to be seen until September.
On Thursday, July 4, Earth will reach aphelion, its maximum distance from the sun for this year. The aphelion distance of 94,511,180 miles (152.1 million km) is 1.67% farther from the sun than the mean Earth-sun separation of 92,955,807.3 miles (149,597,870.7 km), which is also defined to be 1 Astronomical Unit (1 AU). Earth's perihelion (minimum distance from the sun) will occur on January 4.
Earth — is at aphelion, farthest from the sun for the year, at 6:11 p.m. EDT. Our planet is then 94,513,221 miles from the sun (measured center to center), 3.3 percent farther than we were at perihelion in January.
Mars will spend July very low in the western evening sky among the stars of Cancer, shining at magnitude 1.8. The red planet will become increasingly difficult to spot in the twilit sky as it descends steadily towards the sun and solar conjunction in early September. On July 3, the young crescent moon will be positioned less than 3 degrees to the lower right (west) of Mars and 5.5 degrees to the right of Mercury. Observers in the eastern tip of Africa, the Arabian Peninsula, most of Asia, and Micronesia will see the moon occult Mars on July 4.t 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 — is near Mercury as July begins, but thanks to their low altitude above the west-northwest horizon and placement against the bright evening twilight sky, they're only accessible using binoculars less than an hour after sundown ... and even that will be a very challenging observation. Fading into the sunset fires as July progresses, heading toward superior conjunction in early September.
Extremely bright Jupiter will spend July moving retrograde westward among the stars of southern Ophiuchus; just west of the Milky Way. The planet will be very well placed for evening observing all month, occupying the lower part of the southern sky (above Scorpius) after dusk, and setting in the west a few hours after midnight. During the month, the planet's apparent disk size will decrease slightly from 45.4 to 42.5 arc-seconds, and its brightness will drop from magnitude -2.57 to -2.42 as we increase our distance from the planet. From time to time during July, the little round shadows cast by Jupiter's four Galilean moons will be visible as they cross the planet's disk. On July 4 from 10:36 p.m. to 12:48 a.m. EDT, observers in the Eastern half of North America can watch Io's shadow transit Jupiter with the Great Red Spot. On July 20 from 8:54 to 11:06 p.m. EDT, Io's shadow will transit Jupiter again.
Jupiter — is a bright beacon shining at magnitude -2.5 in the south-southeast at nightfall. Look for fainter, ruddy Antares flickering into view 7½ degrees to its lower right. Early evening, when the atmosphere is steady, is the best time to study the often copious detail visible on Jupiter in medium and large telescopes. Later in the evening, Jupiter and Antares move lower in the southwest. On the evening of July 13th, a waxing gibbous moon will sit several degrees to the left of the big planet.
During July, Saturn will be well-positioned for observing all night while it moves retrograde (westward) through the stars of northeastern Sagittarius. Look for it as a medium-bright, yellowish object in the lower part of the southeastern sky, sitting east of the Milky Way. The ringed planet will reach opposition on July 9. On that night, Saturn will rise at sunset. Its minimum separation from Earth of 9.0 AU (839,472 miles or 1,351 million km) will cause Saturn to shine at a maximum brightness of magnitude +0.05 and exhibit an apparent disk diameter of 18.4 arc-seconds. The rings, which will narrow every year until the spring of 2025, will subtend 42.86 arc-seconds across. On July 15, the bright, nearly full moon will be positioned 2.5 degrees to the right (west) of Saturn.
Saturn — arrives at opposition to the sun on July 9th. Shining at magnitude +0.1, it's one of the brightest and easiest "stars" of the warm July night. The ringed planet rises at sunset and shines low in the southeast by the time twilight fades to dark. But Saturn still requires another hour or so to reach a decent altitude for telescopic viewing — especially early in the month, and especially for observers at northern latitudes. It transits the meridian (is due south) at 1:35 a.m. local daylight time on July 1st and by 11:30 p.m. by July's end. The rings of Saturn can be seen in any telescope that magnifies at least 25 times, but the larger the aperture and the sharper the image, the more the detail that can be made out. During the overnight hours of July 15-16, watch as an almost-full moon slowly creeps toward Saturn. As darkness falls, the ringed world glows about 2½ degrees to the moon's left. By midnight the moon has inched noticeably closer, with Saturn appearing to the moon's upper left. By 3 a.m., they are separated by only 1 degree with Saturn now hovering directly above the moon. They will get even closer as they drop toward the west-southwest horizon at dawn.
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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.