Tuesday, July 14
Jupiter reaches opposition at 4 A.M. EDT. At that time, the gas giant will sit 385 million miles (619 million km) from Earth. You can catch it this morning in the southwestern sky, blazing at magnitude –2.8 in the constellation Sagittarius. Its disk spans 48" and at the time of opposition, all four of its Galilean moons will be on display. But act fast — by 4:17 A.M. EDT, Europa will disappear behind the planet’s western limb. It won’t reappear before sunrise.
6.8° east of Jupiter is magnitude 0.1 Saturn, on its way to its own opposition early next week. Its disk currently spans 18" and its rings stretch nearly 42" east-west. The nearly 3,000-mile-wide (4,800 km) Cassini Division is on full display.
The Moon passes 4° south of Uranus at 8 A.M. EDT. You can catch the magnitude 5.8 ice giant easily with binoculars or a small scope in the predawn hours. It currently lies in Aries, roughly halfway along an invisible line drawn between the bright stars Hamal and Menkar. An hour before sunrise, Earth’s satellite has already approached to within 10.8° of the planet, lying directly east of the ice giant.
Today also marks the 55th anniversary of Mariner 4’s flyby of Mars — the first successful Red Planet flyby ever achieved. It is the 5th anniversary of New Horizons’ flyby of Pluto, also the first of its kind.
Pluto reaches opposition tomorrow afternoon, so keep scrolling to find out how to observe it.
Wednesday, July 15
Pluto reaches opposition at 3 P.M. EDT. The tiny world shines at magnitude 14.3 and is 3.07 billion miles (4.95 billion km) from Earth. Nestled close to Jupiter and Saturn in the sky, Pluto is visible all night, with the best viewing later in the evening and early into tomorrow morning, when it’s highest above the horizon.
To find it, center bright Jupiter in your scope — you can’t miss it. Pluto is about 1.8° east-southeast of the gas giant, with a disk less than an arcsecond across. If you can spot it visually, it will simply appear as a dim, dull “star.” Imaging through larger scopes with even a simple digital camera should help reveal it.
The New Horizons flyby, now five years ago, revolutionized our understanding of the dwarf planet. Although the spacecraft’s brief visit is long over, its data is still revealing new details, including the possibility that
Pluto formed “hot” through collisions, rather than through “cold” material slowly building up over time in the outer solar system.