Delta Aquarids, Perseids: Watch Meteor Showers On Peninsula

LOS ALTOS, CA — After a dearth of few months, summer meteor showers are firing up, and now is a perfect time to scope out a dark sky near Los Altos. First up is the Delta Aquarid meteor shower. Consider it a dress rehearsal for the highly anticipated and sky-party worthy Perseid meteor shower. The two showers overlap in early August, and both are already active.

Over the few days, we’re expecting partly to mostly cloudy skies as the week progresses with pleasant temperatures dropping to 56 degrees at their lowest.

The Delta Aquarids, which officially started July 12 and run through Aug. 23, favor the Southern Hemisphere, but the show is still visible from mid-northern latitudes. They’ll peak here around July 28, producing around 10 to 20 meteors an hour. An approaching new moon on July 31-Aug. 1, will make for optimum viewing conditions.

The best viewing times are after midnight and before dawn, regardless of your time zones.

Earthsky.org says one of the best places to watch meteor showers in Los Altos is at the Monte Bello Open Space Preserve parking lot at 4185 Page Mill Road where: "At 2200 feet, this large parking lot is the closest and easiest place to stargaze in the San Francisco Bay Area. You need a special use permit from the Open Space district, which is easy to get."

Sure, the glaring lights of the Silicon Valley are right there — but on days where there is a low marine layer or even is there isn't — this is a great place to see planets, the moon and thousands more stars than you can see from anywhere below."

The Perseids, which began July 17 and last through Aug. 24, will likely produce about 10-15 visible meteors per hour because the moon will be very close to full during the peak dates, from around Aug.11-13.

Earthsky advises those who are serious about seeing meteors not to be daunted. Instead, start watching for the Perseids in the pre-dawn hours from Aug. 9 through Aug. 11. On those dates, there will be more moon-free viewing time than during the peak dates.

In Los Altos, the moon sets at 1:22 a.m., 2:03 a.m., 2:49 a.m., 3:39 a.m. and 4:33 a.m., respectively, on Aug. 9, Aug. 10, Aug. 11, Aug. 12 and Aug. 13.

In years without moonlight, the Perseids are visible at much higher rates, and in outburst years, such as 2016, they can fly at a rate of 150-200 meteors an hour.

“Unfortunately, the moon will be very close to full on the night of the peak, which will wash out the fainter Perseids,” NASA meteor expert Bill Cooke told Space.com.

Still, don’t skip this summertime favorite.

“The Perseids are rich in fireballs, so you'll still see Perseids,” Cooke said. “You just won't see the show you've seen on nights when the moon has not been around.”

And though the meteor shower is most visible after midnight, skywatchers may see a sprinkling of meteors from mid-to-late evening. A rare earthgrazer — a long, slow, colorful meteor along the horizon — is also possible during the evening. Earthsky said Perseid earthgrazers occur before midnight because the radiant point of the shower is close to the horizon.

So, with the Delta Aquarids and Perseids flying at the same time, how will skywatchers know the difference? They’ll need to find the radiant point, especially for the Delta Aquarids.

The Perseids radiate from the constellation Perseus, named after the hero Perseus in Greek mythology, near the famous Double Cluster. The constellation is found in the northern sky and is one of the largest. Finding the radiant point for the Perseids isn’t necessary because they fly in all parts of the sky.

The Delta Aquarids,when traced backward, appear to radiate from a point in front of the constellation Aquarius the Water Bearer, which arcs across the southern sky in North America. The radiant point for the Delta Aquarids nearly aligns with the star Skat (Delta Aquarii), for which the shower is named.

For both showers, find a dark, open sky. Be patient. It’ll take your eyes about 20 minutes to adjust to the darkness, and set aside at least an hour to view them. They can come in spurts, and there can be a lull between shooting stars. Bring along a blanket or reclining lawn chair and settle in to enjoy the show.