This month Jupiter and Saturn dominate the evening sky. Venus climbs into prominence as a predawn planet.
On July 3, our brilliant sister planet begins a 10-day glide across the face of Taurus, the bull, represented by the V-shaped Hyades star cluster. On the 12th, Venus passes just one degree from Aldebaran, the eye of the bull, which is not part of the Hyades.
Don’t miss the show on the 17th, when a waning crescent moon joins Venus and Aldebaran.
Jupiter and Saturn are low in the southeast at nightfall. Much brighter Jupiter and the ringed planet both reach opposition this month, when Earth laps them in the orbital race and they appear opposite the sun in the sky. Jupiter’s opposition comes on the 14th, Saturn’s on the 20th. But Mars will be fairly high at its October opposition because by then we will tilt more toward the night sky than toward the sun. As its opposition date approaches, Mars brightens daily, but it’s still a morning planet.
July’s full moon arrives shortly before midnight on the 4th. Between 10:07 p.m. and 12:52 a.m. that night, the moon’s uppermost part undergoes a penumbral eclipse, where Earth blocks some sunlight from reaching the moon.
Also on July 4, Earth reaches aphelion, its farthest point from the sun. At that moment we’ll be 94.5 million miles from our parent star and traveling most slowly in our orbit. Because Earth reaches its minimum speed in the northern summer, it takes longer to get through this part of our orbit. As a result, in the Northern Hemisphere, spring and summer together last several days longer than fall and winter.
Deane Morrison is a writer and editor with the University of Minnesota Office of University Relations. Minnesota Starwatch is a service of the Minnesota Institute for Astrophysics.