Venus is the brightest planet, and it’s very prominent this month in the west after sunset. Throughout July, Venus appears as a dazzling evening “star.” Look for Venus to adorn the western evening sky until October 2018.
At mid-northern latitudes, Venus attained its highest altitude as the evening “star” in June 2018. That’s in spite of the fact that Venus’ greatest elongation (maximum angular distance from the setting sun) won’t occur until August 17, 2018. At mid-northern latitudes, Venus sets roughly 2 1/2 hours after the sun in early July. By the month’s end, that’ll taper to about 2 hours after sunset.
In the Southern Hemisphere, Venus’ altitude will increase day by day all month long. At temperate latitudes in the Southern Hemisphere, Venus sets about three hours after the sun in early July. By the month’s end, that’ll increase to about 3 1/2 hours after sunset.
Circle July 14, 15 and 16 on your calendar. That’s when the young moon will be sweeping past Venus (and Mercury) in the evening sky. The western twilight will make the pairing all the more picturesque.
Mercury, the innermost planet of the solar system, moved out of the morning sky and into the evening sky on June 6, 2018. The first few weeks of July 2018 will present a good time to spot Mercury beneath Venus in the western evening twilight. In fact, this will the year’s best evening apparition of Mercury for the Southern Hemisphere, though it’ll still be a decent appearance for mid-northern latitudes.
Mercury will reach its greatest elongation from the sun on July 12, 2018, and its reign as the evening “star” will extend all the way through July 2018. Look for the young crescent moon to pair up with Mercury on or near July 14.
Jupiter is still bright and beautiful throughout July 2018. Our planet Earth passed between the sun and Jupiter – bringing the planet to opposition – on the night of May 8-9, 2018. In the Northern Hemisphere, you’ll find Jupiter highest up for the night around dusk or nightfall, and in your southern sky; in the Southern Hemisphere, you’ll see Jupiter highest up (and nearly overhead) at early evening. Jupiter is brighter than any star, but it’s not brighter than Venus, which is in the west after sunset.
Jupiter and Mars are about the same brightness in early July. But that’ll change as Mars brightens throughout the month, to supersede Jupiter as the 4th-brightest celestial object, after the sun, moon and Venus.
Jupiter shines in front of the constellation Libra the Scales until November 2018. Look for Libra’s brightest stars near Jupiter, Zubenelgenubi and Zubeneschamali (both star names are pronounced with the same rhythm as Obi-Wan Kenobi, of “Star Wars”).
If you aim binoculars at Zubenelgenubi, you’ll see this star as two stars. Zubeneschamali, meanwhile, is said to appear green in color, although, astronomers say, stars can’t look green.
Saturn and Mars rise into the southeast sky after nightfall in early July. At the beginning of the month, Saturn rises a touch before sunset and Mars rises at about the time that Venus sets. Near the month’s end, at Mars’ opposition, Mars rises at about the time that the sun sets (and Saturn about two hours before sunset). Throughout the month, Mars rises about two hours after Saturn does.
Click here for recommended sky almanacs; they can give you the rising times of the planets.
Around midnight offers a better view of Saturn and Mars, as these worlds are seen much higher up in the sky than they are at nightfall or early evening.
You can tell Mars from Saturn because Mars has a reddish color and Saturn looks golden. Binoculars show their colors better than the eye alone.
Read more: Century’s longest eclipse on July 27
At present, both Saturn and Mars shine more brilliantly than a 1st-magnitude star. However, Mars is brighter than Saturn. Saturn’s brilliance peaked at its June 27 opposition, and Mars’ brilliance will increase until it peaks at its July 27 opposition.
But Saturn’s brightness increase has been rather subtle, while Mars’ will prove to be more dramatic! At the beginning of July, Mars shines about eight times brighter than Saturn, whereas by the month’s end, Mars exceeds the brilliance of the ringed planet by some 15 times.
It’s not often that Mars outshines Jupiter, normally the fourth-brightest celestial object to light up the sky, after the sun, moon and Venus. But, for a couple of months in 2018, Mars will outshine Jupiter from about July 7 to September 7, 2018.
Remember Mars’ historically close opposition of August 28, 2003? That year, it was closer and brighter than it had been in some 60,000 years. This upcoming July opposition will be the best since 2003.
What do we mean by bright planet? By bright planet, we mean any solar system planet that is easily visible without an optical aid and that has been watched by our ancestors since time immemorial. In their outward order from the sun, the five bright planets are Mercury, Venus, Mars, Jupiter and Saturn. These planets actually do appear bright in our sky. They are typically as bright as – or brighter than – the brightest stars. Plus, these relatively nearby worlds tend to shine with a steadier light than the distant, twinkling stars. You can spot them, and come to know them as faithful friends, if you try.
Bottom line: In July 2018, at evening dusk/nightfall, Venus appears in the west whereas Jupiter shines in the south (Northern Hemisphere) or high overhead (Southern Hemisphere). In early July, Mars rises as Venus sets; and by late July, Mars comes up at sunset. Mercury may be seen in the evening sky, at dusk, beneath Venus. Click here for recommended almanacs; they can help you know when the planets rise, transit and set in your sky.
Bruce McClure has served as lead writer for EarthSky's popular Tonight pages since 2004. He's a sundial aficionado, whose love for the heavens has taken him to Lake Titicaca in Bolivia and sailing in the North Atlantic, where he earned his celestial navigation certificate through the School of Ocean Sailing and Navigation. He also writes and hosts public astronomy programs and planetarium programs in and around his home in upstate New York.