Saturday, August 28
The Moon passes 1.5° south of Uranus at 5 A.M. EDT. You’ll find the pair high in the southern sky at that time, sitting in southeastern Aries the Ram. To their northwest is Aries’ alpha star, 2nd-magnitude Hamal. To their south (directly below them) is the head of Cetus the Whale, marked by the bright (magnitude 2.5) star Menkar. And to the pair’s northeast is the Pleiades star cluster (M45), often visible as a tiny, dipper-shaped asterism in Taurus the Bull.
Our Moon is slightly more than half-lit; above it, Uranus glows a soft magnitude 5.8, just at the edge of naked-eye visibility. The Moon’s light, however, will likely wash the planet out, so your best bet is to find its 4"-wide, bluish-gray disk with a pair of binoculars or a small telescope. Slightly closer to the Moon, just under 1° from our satellite’s northern limb, is the magnitude 5.5 star Sigma (σ) Arietis.
Sunrise: 6:24 A.M.
Sunset: 7:37 P.M.
Moonrise: 10:55 P.M.
Moonset: 12:32 P.M.
Moon Phase: Waning gibbous (65%)
Sunday, August 29
Corona Borealis the Northern Crown is a little-known but easy constellation to find. After sunset tonight, locate bright Arcturus (magnitude –0.1) about 40° high in the west. With Sirius still below the horizon, Arcturus is the brightest star Northern Hemisphere observers will see in the sky. (To that star’s lower left, much closer to the horizon, shines brilliant Venus at magnitude –4.)
About 20° above Arcturus is the curve of Corona Borealis. Magnitude 2.2 Alphecca, which sits west of the center of the constellation’s semicircular shape, is the Crown’s alpha star. Its beta star, just northwest of Alphecca, is named Nusukan. The Crown can be drawn from seven stars: moving counterclockwise, these are Iota (ι), Epsilon (ϵ), Delta (δ), Gamma (γ), Alpha (α), Beta (β), and Theta (θ) Coronae Borealis.
The Moon reaches apogee, the farthest point from Earth in its orbit around our planet, at 10:22 P.M. EDT. At that time, it will sit 251,096 miles (404,100 kilometers) away.
Sunrise: 6:25 A.M.
Sunset: 7:36 P.M.
Moonrise: 11:26 P.M.
Moonset: 1:33 P.M.
Moon Phase: Waning gibbous (56%)
Monday, August 30
Last Quarter Moon occurs early this morning at 3:13 A.M. EDT. Early risers should certainly take the time to enjoy our satellite’s partly lit face, visible above the V in Taurus, where the Hyades open star cluster sits. About 5.5° below the Moon is Aldebaran, the bright red eye of the Bull.
Even if you don’t want to get up early, you’ll be able to check out the Moon until after noon in most U.S. time zones. The best — and easiest feature — to find is the terminator, which is the line where night meets day on the lunar surface. Surface features stand out most in this area, where the shadows are sharpest.
The Last Quarter Moon can also show us the direction of Earth’s orbital motion. That’s because during this phase, the Moon’s location in its orbit around Earth just happens to be in line with the exact direction Earth is moving through space as it orbits the Sun. Looking up at the Last Quarter Moon shows the space Earth itself will occupy about three and a half hours later.
Sunrise: 6:26 A.M.
Sunset: 7:34 P.M.
Moonrise: —
Moonset: 2:32 P.M.
Moon Phase: Waning crescent (46%)
Tuesday, August 31
Mars, Mercury, and Venus stand in a line behind the setting Sun this evening. Faint Mars will likely sink out of sight too quickly to easily find, but brighter Mercury (magnitude 0) is 3.5° high in the west 30 minutes after sunset. Far easier to spot is magnitude –4 Venus, 16° east-southeast of Mercury and less than 6° from Spica, Virgo the Maiden’s brightest star. See how long it takes for this luminary to appear against the darkening twilight, sitting to the upper left of Venus. Over the next week, Venus will approach and then pass by this star, moving farther east along the ecliptic.
For those with a clear view of the horizon, turn a telescope on Mercury once the Sun has completely disappeared. The planet’s face is 74 percent illuminated and spans just 6". Venus is nearly three times this size, showing a 73-percent-lit face.
Sunrise: 6:27 A.M.
Sunset: 7:33 P.M.
Moonrise: 12:02 A.M.
Moonset: 3:31 P.M.
Moon Phase: Waning crescent (37%)