What planetary events are coming up in the night sky? Read about Venus, Mercury, Mars, Jupiter, Saturn, Uranus and Neptune and what’s going on in our Solar System in Planets at a Glance.
From mid-northern latitudes, Mercury will be visible with increasing difficulty during the first 10 days of July, when it will shine very low over the northeastern horizon just before sunrise. More southerly observers will be able to view the speedy planet more easily. As Mercury shifts towards the Sun each morning, it will diminish in brightness. Telescope views will reveal a shrinking, waxing gibbous phase. The planet will then become unobservable until after it passes the Sun at superior conjunction on July 16. During the final third of the month, Mercury will reappear just above the west-northwestern horizon for a short window of time after sunset. It will brighten to magnitude -0.6 at month’s end, when the best viewing period will occur just after 8:30 p.m. local time. Mercury’s late-July apparition will be only so-so from mid-northern latitudes, but quite good from the tropics. On July 29, the young crescent Moon will shine two finger widths to the upper right (or celestial north) of the planet.
Venus will continue to gleam brilliantly in the east-northeastern pre-dawn sky during July. Its angle from the Sun will decrease from 30 to 22 degrees. That will hold it rather low in the sky for mid-northern observers and steadily reduce their viewing time before sunrise, but Venus will continue to put on a splendid showing for observers in the tropics and farther south. Venus’ easterly motion will carry it between the horns of Taurus until mid-month. It will spend July 16-18 in northern Orion and then enter the stars of Gemini, dancing with Castor’s bright foot stars Propus and Tejat Posterior on July 20 and 21, respectively. Venus will shine at a very bright magnitude -3.9 all month long. In a telescope, it will display a disk size that shrinks from 12 to 11 arcseconds while its illuminated phase increases from 86 per cent to 92 per cent. On July 26, the pretty, old crescent Moon will shine several finger widths to the upper left (or celestial north) of Venus.
Mars will continue to gradually brighten in July (from magnitude 0.46 to 0.21) as the Earth-Mars distance is reduced. The red planet will be shining in the eastern pre-dawn sky to the lower left of much brighter Jupiter from the wee hours of the morning until almost dawn. Mars’ easterly orbital motion through Pisces until July 8, and then in Aries for the rest of the month, will cause it to rise about two minutes earlier each morning. That will steadily increase its separation from Jupiter and will result in Mars rising just after midnight local time at month’s end. Telescope views of Mars will show an 86-per-cent illuminated, ochre disk with mere hints of the dark markings that will be obvious come December. Over the month, the planet’s apparent disk size will grow from 7.2 to 8.2 arcseconds. The end of July will see Mars approaching the much fainter planet Uranus from the upper right (or celestial west). They’ll be binoculars-close from July 25 onwards. On July 31, the red and blue planets will be cosy enough to share the eyepiece of a low magnification telescope. (Their closest approach will occur on August 2.) On July 21 the waning crescent Moon will shine several finger widths to the upper right (or celestial west) of Mars. Hours later, observers in eastern China, Japan, and northeastern Russia can watch the Moon occult Mars, on the morning of July 22 around 15:00 UTC.
Bright, white Jupiter will spend July sliding slowly across the stars in the northwestern corner of Cetus – bracketed by reddish Mars off to its left (or celestial northeast) and yellowish Saturn well to its right (or celestial southwest). Jupiter’s easterly prograde motion will slow to a stop on July 29 in preparation for it to enter a westerly retrograde loop that will last until late November. In early July, the magnitude -2.45 planet will rise over the eastern horizon at around 12:40 a.m. local time and then gleam while it climbs into the southeastern sky until the sunrise hides it. From mid-July onward, Jupiter will rise before midnight local time, joining Saturn and Neptune, and kicking summer evening planet-viewing into next gear. Jupiter will be an excellent telescope target during July. Its four Galilean moons will dance to the east and west of its banded orb, which will grow in apparent size from 41 to 45 arcseconds. The Great Red Spot will appear every second or third morning, and the small, round, black shadow of one of the Galilean moons will transit the planet on July 8, 11, 15, and 31. On July 19 the waning gibbous Moon will shine just below (or celestial southeast of) Jupiter, making a nice photo opportunity.
Creamy coloured Saturn has been part of the late evening sky since it began to rise before midnight in mid-June. Because it will rise about four minutes earlier each night, the ringed planet will be clearing the treetops by about 10 p.m. local time toward the end of July, giving us plenty of overnight observing hours. Saturn’s slow westerly retrograde motion will be apparent as it slides past the medium-bright tail star of Capricornus, Deneb Algedi, which will twinkle a thumb’s width below the planet. Saturn will brighten slightly during July as we approach its opposition on August 14. Viewed in a backyard telescope, Saturn’s 18.5 arcseconds-wide globe, adorned with its 43 arcseconds-wide ring system, will be surrounded by a number of its brightest moons. The rings will progressively become more edge-on in appearance until March 2025, so a greater amount of Saturn’s southern hemisphere will be extended below its ring plane this year. The waning gibbous Moon will pass less than 6 degrees below (or celestial southeast) of Saturn on July 15.
During July, Uranus will be observable in the lower part of the eastern sky for an hour or two before dawn. The planet’s magnitude 5.8, blue-green dot will be visible in binoculars and backyard telescopes as it shifts slowly eastward through the stars of southeastern Aries. At the end of July Mars will be approaching Uranus from the upper right (or celestial southwest). They’ll be binoculars-close from July 25 onwards. On July 31, the red and blue planetary duo will be close enough to share the eyepiece of a low magnification telescope. (Their closest approach will occur on August 2.) On July 22 the waning crescent Moon will shine a thumb’s width to the lower left (celestial east) of Uranus. Hours earlier, observers from northeastern Brazil to the Cape Verde Islands and northwestern Africa can watch the Moon occult Uranus around 04:30 UTC – the sixth of 15 consecutive monthly lunar occultations of the seventh planet.
As July opens, the distant, blue, magnitude 7.9 planet Neptune will begin to rise before midnight local time, and thereafter about four minutes earlier each night. Throughout the month Neptune will be creeping west through the stars along the Pisces/Aquarius border – positioned about 13 degrees to the upper right (or celestial southwest) of far brighter Jupiter. The best times for viewing Neptune through good binoculars and backyard telescopes will be in the dark sky preceding dawn. In a telescope, Neptune will show a disk 2.3 arcseconds wide. On July 18, the bright, waning gibbous Moon will shine 4 degrees below (or celestial southeast of) Neptune.
Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the Universe together.