Sunrise and Sunset Times (Eastern Time): The sun rises at 6:00 am and sets at 8:16 pm on August 1; The sun rises at 6:28 am and sets at 7:36 pm on August 31.
August Moon Phases — Full “Sturgeon Moon” on August 11; New Moon on August 27.
stars and constellations
As darkness falls on August evenings, the constellations of summer, and also some left over from spring, begin to emerge from the twilight glow. Looking north, the Big Dipper, a part of the spring constellation Ursa Major, dips to the northwest. The two front stars in the Big Dipper point to Polaris, the North Star, while the arc of the Big Dipper’s handle leads to the orange giant star Arcturus, which is high in the west. Arcturus is only 37 light-years away, while most of the stars in the Ursa Major cluster are about 80 light-years from us. But Polaris is 430 light-years away, or more than 10 times farther than Arcturus and 5 times farther than the stars that make up the Big Dipper.
Extending above Polaris is Little Dipper, the most famous asterism within Ursa Minor, Little Bear. Snaking around Little Dipper is Draco the Dragon, a large but relatively faint summer constellation. Draco is especially notable because one of its stars, Alpha Draconis, or Thuban (meaning “serpent”), was the pole star some 4,700 years ago, around the time the Egyptian pyramids were being built. Thuban is only one fifth as bright as Polaris
Looking south, get one last glimpse of springtime star Spica in Virgo as it sets in the southwest. To the far left of Spica is orange-red Antares in Scorpius, which lies low to the south-southwest. The body of the Scorpion snakes towards the horizon and then upwards in a curved stinger. The “cat’s eyes”, a pair of unevenly bright stars, Shaula and Lesath, are located at the end of the tail. To the upper left of the cat’s eyes is the Sagittarius “teapot,” an easy-to-identify grouping. And the Summer Triangle, consisting of Vega in the constellation Lyra, Deneb in Cygnus, and Altair in Aquila, sits high in the east-northeast.
During late afternoon, the W-shaped constellation Cassiopeia rises in the northeast. Also, the Great Square of Pegasus, consisting of four rectangle-shaped stars meeting at its edge, can be seen rising in the east. The rise of Cassiopeia and Pegasus over the eastern horizon can only mean one thing: the fall season awaits us on our doorstep.
Naked eye planets in the evening and morning sky
Mercury leads the parade of planets across the night sky from dusk to dawn this August; Mercury appears as a bright star quite low in the west about 30 minutes after sunset. Mercury’s visibility at dusk improves toward the end of August; it reaches its maximum brightness and greatest elongation with the Sun on the 27th.
Saturn is in opposition to the Sun on August 13, when it reaches its maximum brightness (since it is at its closest point to Earth) and is also visible all night, rising at sunset, standing due south at midnight and setting at dawn. Cream-colored Saturn stands out among the faint stars of Capricorn and is clearly brighter than Altair, which is high above it, but much fainter than Jupiter, which rises a couple of hours later. Even a small telescope will clearly reveal Saturn’s beautiful ring system and its largest moon, Titan.
Jupiter resides in the non-zodiac constellation Cetus the Whale, just below the southern border of Pisces, and well to the east of its gas giant brother Saturn, which it trails by 2 hours. Bright Jupiter looms over the eastern horizon a few minutes before 11 pm EDT on August 1 and 8:30 pm on the 31st. Jupiter’s spin in opposition to the Sun occurs next month on September 26th.
Mars continues to shine steadily as it moves toward its closest point to Earth in December. While Mars isn’t as bright as Jupiter (or Venus), it now easily outshines Saturn and rivals the night sky’s brightest luminaries, Vega and Arcturus. Mars rises after midnight, at 12:30 am, or almost 2 hours after Jupiter, at the beginning of August, and an hour earlier at the end of the month. Look for what appears to be a bright orange star above the eastern horizon a half hour after it rises, and high to the south in the first light of dawn.
Venus is the dazzling “morning star” low on the northeastern horizon at sunrise. In early August, Venus rises just after 4:15 a.m. EDT, less than two hours before sunrise. At the end of the month, Venus rises around 5:15 a.m., or just a little over an hour before sunrise. Venus will pass behind the Sun (superior conjunction) in late October and then gradually reappear at dusk.
Around the night of August 12-13, Earth will pass through debris from comet Swift-Tuttle, producing the Perseid meteor shower. The meteorites will appear to radiate from the Perseus constellation, but can be seen anywhere in the sky. Unfortunately, this year the Moon will be a day past full, so the bright moonlight will wash out all but the brightest meteors.
Astronomy question for August: Why does the pole star always stay in the same position in the sky? (Answer will be provided in next month’s column.)
Answer to last month’s question: The aurora borealis (and aurora australis in the southern hemisphere) occur when the Sun emits large bursts of electrically charged particles (electrons, protons), especially during periods of high sunspot activity. As they stream out into the solar system, some of these particles become trapped by Earth’s magnetic field and funneled toward the polar regions, where they collide with atmospheric nitrogen and oxygen molecules, causing them to glow with a typical greenish or reddish.
Harry J. Augensen is Professor Emeritus of Physics and Astronomy at Widener University. Astronomical information is taken from The Astronomical Almanac (2021-2025) by Richard J. Bartlett, and from Astronomical Calendar 2022 by Guy Ottewell, available online at https://www.universalworkshop.com/astronomical-calendar-2022/. For more information about the night sky, visit the Widener Observatory stargazing website at http://www.widener.edu/stargazing/. A set of free sky maps can be obtained from http://www.skymaps.com/.