Comet Neowise is receding from us but the Earth is about to plow through the debris field left behind by the comet 109P/Swift-Tuttle. We’ll see this as the Perseid Meteor shower where dust to pea-size bits of comet material impact the atmosphere and burn up in a trail of glowing ionized gas.
This annual meteor shower occurs over several days, every year, in mid-August. This year, the peak rate is predicted to occur on the night of Tuesday, August 11th at 11:00 pm PDT but Perseid meteors will be active for several days surrounding the peak.
Comet Swift-Tuttle is a periodic comet that makes a return trip close to the Sun and Earth every 133 years. It comes a little inside Earth’s orbit at its perihelion before heading back out past Pluto. It has a long history of observations with probable sightings as early as 322 BC and 69 BC. In 188, Chinese records suggest it reached naked-eye 0.1 magnitude. Its last close approach was in 1992 when it was visible with binoculars. The next return trip is not until 2126 when it could again be a bright naked-eye comet at 0.7 magnitude.
Perseid meteors can appear anywhere in the sky but they all seem to originate from a fixed point, called the radiant, near the star Eta Persei in the constellation Perseus – the Hero. From a dark site, you may be able to see as many as 110 meteors per hour. Note that the Moon rises just after midnight, at 12:05 AM, on August 12th and the moonlight will wash out faint meteors during early morning observing. No special equipment is needed to see the meteors – just lie back in a lawn chair or on the ground and look up and perhaps count how many you see.
The MacMillan Space Centre is hosting a Perseid Meteor Shower celebration on Wednesday, August 12th. The in-person star party is sold-out but you can still register to watch a live stream (by donation) – visit the Space Centre’s event info page to register and for more information.