Minnesota Starwatch is a newsletter describing the night sky in the Midwest.
Updated monthly, it is produced by the
Minnesota Starwatch for July 2018
by Deane Morrison
Earth reaches aphelion, its farthest point from the sun, on July 6, when we'll be 94.5 million miles from our parent star. But while giving the sun a wide berth, Earth cozies up to Mars in spectacular fashion. And, like a series of opening acts, other solar system bodies present a parade of celestial pairings.
As the spring constellation Leo dives toward the sunset, the lion's bright heart, Regulus, slips by Venus. On the 9th, the star passes just one degree (two moon widths) from the planet. The morning of the 10th, a waning moon rises close to Aldebaran, the eye of Taurus, the bull. The evening of the 15th, a young crescent moon of the next cycle makes a lovely companion to Venus. The moon goes on to visit Jupiter on the 20th, Saturn on the 24th, and Mars on the 26th and 27th.
At 12:07 a.m. Friday, the 27th, Earth laps Mars in the orbital race. Mars is then at opposition, or opposite the sun in the sky, so it will be up all night. However, that night the moon will be near Mars and almost full, plenty bright enough to steal some of Mars' luster. The evening of the 27th, July's full moon rises even closer to Mars, but as the most distant full moon of 2018, it won't look especially big.
Three nights later—at 2:50 a.m. Tuesday, the 31st—Earth sweeps to just 35,785,000 miles from Mars. This will make Mars the closest and brightest it has been since summer 2003, when our two worlds made their closest approach in nearly 60,000 years. By then the moon will have waned and moved eastward far enough to give Mars a decent head start getting into the sky.
Look for Mars in the southeast after the sky has darkened. If you are on a calm body of water, enjoy its shimmering reflection.
Shining above Mars, the Summer Triangle of bright stars is now well up in the east after nightfall. Brightest is Vega, in Lyra, the lyre, at the northwest corner of the Triangle. Below Vega is Altair, in Aquila, the eagle, the southern point of the Triangle. And in the northeast corner, Deneb anchors the Northern Cross, which outlines the graceful form of Cygnus, the swan.
West of the Triangle, brilliant Arcturus, in kite-shaped Bootes, the herdsman, outshines even Vega. Immediately east of Bootes hangs Corona Borealis, the northern crown. Its neighbor to the east is an hourglass of stars marking the upside-down body of Hercules.
With all these bright stars and planets up at the same time, this July's evening sky promises to be one of the most memorable.
The University of Minnesota offers public viewings of the night sky at its Duluth and Twin Cities campuses. For more information and viewing schedules, see:
Duluth, Marshall W. Alworth Planetarium: www.d.umn.edu/planet
Twin Cities, Minnesota Institute for Astrophysics (during fall and spring semesters): www.astro.umn.edu/outreach/pubnight
Check out the astronomy programs at the University of Minnesota's Bell Museum ExploraDome: www.bellmuseum.umn.edu/ForGroups/ExploraDome/index.htm
06/21/18 Contact: Deane Morrison, University Relations, (612) 624-2346,
Find U of M astronomers and links to the world of astronomy at http://www.astro.umn.edu.