The Perseid meteor shower – August 11 and 12
In my experience, the highlight of every summer is the annual Perseid meteor shower, which this year peaks on the evenings of August 11 and 12. This is consistently the best meteor show of the year, and the fact that it occurs on usually mild nights makes it one of the most pleasant displays to watch.
Every year around this time, the Earth passes through debris streams of particles that pollute the path of the periodic comet Swift-Tuttle, which orbits the Sun in a long, circular orbit every 133 years. The comet was discovered by astronomers Lewis Swift and Horace Tuttle in July 1862 and linked to the Perseids by Italian astronomer Giovanni Schiaparelli in 1866. A later search of ancient records first mentioned the shower in 36 AD.
The Perseids are active from mid-July to late August. Their name derives from the point in the sky from which the members of the shower appear to radiate in the constellation Perseus, which rises into the northeastern sky after midnight.
The Perseids are fast, often leaving “loops” lasting several seconds after they flash across the sky. A single observer in a dark location can expect to see as many as 100 Perseids at peak time early on the morning of the 12th. The waxing Moon will set at 1 a.m. local time, giving you a few hours of quality darkness.
The Return of the Planets
It’s been a while since bright planets graced our skies, but that’s about to change. Those who watch the sky late in the evening or early in the morning will be able to keep an eye on a number of our fellow wanderers in the solar system.
For most of July and August, the action takes place in the morning sky, where you’ll find Saturn, Mars, and Jupiter. Saturn rises first, reaching the southeastern horizon around midnight in mid-July and around 9 p.m. in mid-August. Saturn reaches opposition, rising at sunset and setting at sunrise on September 8.
Saturn is approaching one of its equinoxes, which occur every 15 years, and its famous rings are now at a very small angle to Earth, appearing as two spikes framing the planet’s disk.
Red Mars and bright Jupiter will greet early risers at dawn in July, but both are well positioned in the eastern sky to be observed by people hoping to see the Perseids. On the morning of August 14, the two planets will pass in close conjunction, just a third of a degree apart.
Venus comes into play in mid-August, gradually appearing in the west as evening twilight begins. In September, the dazzling planet will gradually move ahead of the sun. As autumn begins, it will occupy a prominent position in the evening sky for the rest of the year.
Don’t forget the Milky Way!
The backdrop for summer stargazing is the glowing band that traces the star-studded Milky Way, the brightest parts of which arch majestically above us as summer ends and autumn approaches. The amorphous glow you see from dark sky positions is the combined light of some of the hundreds of billions of stars that accompany our sun in a great cosmic spiral vortex.
Three bright stars, Vega, Deneb and Altair, form the Summer Triangle, which is shared by some of the brightest star clouds in the galaxy. Binoculars or a small telescope with low power will break these clouds up into individual stars and star clusters, revealing glowing emission nebulae.
There will be four full moons between the summer solstice and the autumn equinox. They will occur this Saturday (Strawberry Moon), July 21 (Full Goat Moon), August 19 (Full Sturgeon Moon) and September 17 (Harvest Moon).
Four full moons in a single season is unusual; usually there are only three. This leads to one of the definitions of the “Blue Moon,” which, according to a report in the 1937 edition of the Maine Farmer’s Almanac, calls the third full moon of a season a “Blue Moon.” The more popular definition calls the second full moon in a calendar month the “Blue Moon.” This last occurred in August 2023.
Partial lunar eclipse – September 18
Just before the autumn equinox, summer has one last highlight in store for us. The full moon on September 17 will look a little strange as the Earth’s shadow will pass over the northern polar regions in a small partial lunar eclipse. The partial eclipse will occur at 10:44 p.m. Eastern Time in Washington, with about eight percent of the moon obscured.