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 display of the year, and the fact that it takes place on generally mild nights makes it one of the most comfortable to watch.
Every year around this time, Earth passes through debris streams of particles that litter the path of the periodic comet Swift-Tuttle, which orbits the sun in a long, looping orbit every 133 years. The comet was discovered in July 1862 by astronomers Lewis Swift and Horace Tuttle and was linked to the Perseids in 1866 by Italian astronomer Giovanni Schiaparelli. Later searches in ancient archives first mention the shower in the year 36.
The Perseids are active from mid-July to the end of August. Their name is derived from the point in the sky from which the members of the shower appear to radiate into the constellation Perseus, which climbs into the northeastern sky after midnight.
The Perseids are fast and often leave streaks of “trains” lasting for a few seconds after they flash across the sky. A single observer in a dark spot could expect to see as many as 100 Perseids at the peak time early on the morning of the 12th. The waxing moon sets 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 there were bright planets in our sky, but that’s about to change. Late evening and early morning sky watchers will have some of our fellow solar system wanderers to keep an eye on.
For most of July and August, the action takes place in the morning sky, where you can find Saturn, Mars and Jupiter. Saturn rises first, reaching the southeastern horizon around midnight in mid-July and at 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 occurs every fifteen years, and its famous rings are now at a very small angle to Earth. They will appear as two peaks framing the planet’s disk.
Blushing Mars and bright Jupiter will greet early risers at dawn throughout the month of July, but they will both be well positioned in the eastern sky for people looking to catch the Perseids. On the morning of August 14, the two planets will pass in close conjunction, separated by only a third of a degree.
In mid-August, Venus comes into action, gradually appearing in the west as evening twilight begins. As we approach September, the dazzling planet will gradually move ahead of the sun. As autumn progresses, it will climb to 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 luminous band that follows the star-studded Milky Way, the brightest parts of which stretch majestically above us as summer draws to a close. That amorphous glow you see from dark sky locations 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 group, which is split by some of the galaxy’s brightest clouds. Binoculars or a small, low-power telescope will begin to separate these clouds into individual stars and clusters and also show glowing emission nebulae.
There will be four Full Moons between the summer solstice and the autumn equinox. These will take place this Saturday (Strawberry Moon), July 21 (Full Buck Moon), August 19 (Full Sturgeon Moon) and September 17 (Harvest Moon).
Having four full moons in one season is unusual; normally there are only three. This leads to one of the definitions of “Blue Moon,” which, according to an account in the 1937 edition of the Maine Farmer’s Almanac, labels the third full moon of a season as the “Blue Moon.” The more popular definition calls the second full moon in a calendar month the ‘Blue Moon’. This last happened in August 2023.
Partial lunar eclipse – September 18
Summer has one last treat in store for us, just before the autumnal equinox. The full moon on September 17 will look a little strange as Earth’s shadow moves across the northern polar regions during a small partial lunar eclipse. The mid-eclipse will occur at 10:44 PM Eastern time in Washington, at which time about eight percent of the moon will be eclipsed.