Here is a listing of celestial events you might want to look for during these spring/summer nights in August. All times are listed as Eastern Daylight Time for the Northern Hemisphere.
Take note that we sometimes will use angular degrees to define the separation between two objects, such as (for example) the Moon and a bright planet. Keep in mind that the width of your clenched fist, held at arm’s length, measures roughly 10°.
August 1 – We lead off this month with a gathering involving Jupiter and Saturn with the waxing gibbous Moon. Jupiter can be readily found this evening about 3° to the upper right of the Moon, while Saturn is about twice that distance to the Moon’s upper left. Jupiter shines in eastern Sagittarius. This giant world was at opposition on July 14th, so in August it’s already visible in the southeast at dusk and sets before dawn. Jupiter still glares at magnitude -2.7. Its large disk is best observed when the planet is highest in the sky: around 11:30 p.m. local daylight time at the start of August, and 9:30 p.m. by month’s end.
As for Saturn, it shines in the south-southeast during evening hours and like Jupiter, is also in eastern Sagittarius. And with all due respect to Venus, Mars and Jupiter, many would say unequivocally that Saturn is also the most beautiful planet. It never fails to elicit a gasp from someone shown it for the first time through a reasonably good telescope.
The ringed-planet design has so thoroughly imbued our popular culture that many people are amazed to see that such an object actually exists! The famous rings are now tilted 21½° from edge-on, a value that will gradually close to zero by 2025. A cloud belt or two may be detectable on the ball of Saturn itself, and possibly an elusive bit of detail if you have a high-resolution telescope and some luck. And any telescope that shows Saturn’s rings will also show Titan, its largest moon. Titan always appears within four ring-lengths of the planet. It’s that far west of Saturn on August 13th and 29th, and about the same distance east on the 5th and 21st.
Mercury is still visible before sunrise as August begins, but it quickly drops of sight and reaches superior conjunction with the sun on August 17th.
August 3 -Full Sturgeon Moon Moon at 11:59 a.m. In this phase, the visible Moon is fully illuminated by direct sunlight. Though the Moon is only technically in this phase for a few seconds, it is considered “full” for the entire day of the event and appears full for three days. See how this month’s Moon got its many names in our short video, below.
August 6— Midpoint of Summer. Summer is half over.
August 8 – If you’re a night owl, head outside around 11 p.m. local time to see the waning gibbous Moon ascending the eastern sky, accompanied by brilliant Mars situated about 2½° to the Moon’s upper left. As the night wears on, watch how the Moon appears to draw closer to the red planet. They will appear closest during the predawn hours, separated by about a degree. Mars is rising earlier every week and becoming dazzling! At the beginning of August, it comes up soon after 11 p.m. local daylight time, and by the 31st it rises around 9:30 p.m.
Mars is gradually slowing in its nightly eastward progression in the southeast corner of Pisces the Fishes. Drawing ever nearer, Mars doubles in brightness during August, surpassing Sirius on August 21st and reaching magnitude -1.8 by month’s end. By the end of August its disk will have swelled to about 40% of Jupiter’s, which may still look pretty small in a telescope but is enormous compared to how Mars usually appears. Set your alarm clock so you can be out about 4:30 a.m. local daylight time. Mars is best during the first light of dawn when it is high in the south.
August 11 – Last Quarter Moon at 12:45 p.m. In this phase, the Moon appears as a half Moon due to the direct sunlight, the illuminated part is decreasing toward the new Moon phase.
August 11-12 —The Perseid Meteor Shower peaks. Unfortunately, the last-quarter Moon will interfere with the peak of this year’s Perseid display. Otherwise, an observer might witness more than a meteor per minute in a clear, dark sky. Most of these “shooting stars” would be identifiable as Perseids because their paths, extended backwards along the line of flight, would intersect near a point on the Perseus-Cassiopeia border, which gradually climbs the northeast sky after midnight. Better viewing conditions will come a few mornings after the 12th, when predawn skies are darker, but the shower will then be much diminished.
August 12 —Venus rises about the same time all month long: around 2:40 a.m. local daylight time. It accomplishes this by racing eastward against the westward seasonal progression of the constellations, starting the month 2° from Zeta Tauri and ending in eastern Gemini near Cancer. This morning, Perseid watchers will find Venus is at greatest elongation, 46° from the sun, and it will be fascinating to observe in a telescope within a few days of this date, appearing exactly half-lit in telescopes, though not necessarily on the 12th itself.
August 15 – Looking east, check out the slender crescent Moon and Venus giving us a “wink” before sunrise. Venus will sit to the lower right of the Moon.
August 18 – New Moon at 10:42 p.m. In this phase, the Moon is not illuminated by direct sunlight and is completely invisible to the naked eye.
August 25 – First Quarter Moon at 1:58 p.m. In this phase, the Moon looks like a half-Moon in the sky. One-half of the Moon is illuminated by direct sunlight while the illuminated part is increasing, on its way to becoming a full Moon.
August 28 – The Moon has a second encounter with Jupiter this month, passing about 2° below it as darkness falls this evening. Well to the left (east) of this duo is Saturn. The Moon will slide past Saturn during the midday hours on the 29th. By that evening, you’ll find the ringed world 5° to the Moon’s upper right.
Our schedule is adapted from “Skylog,” a regular feature appearing in Natural History magazine, written by Mr. Rao since 1995.