On Wednesday night, the Perseid meteor shower, a once-a-year celestial event, is scheduled to return.
It is expected to peak before dawn on Thursday, August 12, though the display may put on a fine show for several nights prior to and following. Also, it is believed that this year’s conditions are as near to perfect as can be. The waxing crescent Moon sets around 10 p.m. Local time, which means until dawn, dark, Moonless skies.
Astronomy enthusiasts will get the best views of meteors shortly after evening twilight ends. By that time, the radiant of the shower – its perspective origin in the constellation Perseus – will have risen above the northeastern horizon. The few Perseids visible this early will be spectacularly long “earthgrazers” skimming across the top of the atmosphere. The higher the radiant, the more meteors you’ll see — as Perseus ascends higher in the northeast, particularly after midnight, more meteors will appear throughout the sky.
The Perseid meteor shower does not require any special equipment to enjoy. All you need to do is find a dark spot away from bright lights, preferably with a wide-open view all around.
According to Diana Hannikainen, Sky & Telescope’s Observing Editor, comfort is critical for fully enjoying the show.
“You’ll want to be comfortable in order to enjoy the show fully — craning your neck for several hours can ruin the experience,” Diana Hannikainen advised.
Bring a reclining lawn chair or a ground cloth to enable you to lie down comfortably. Wrap yourself in blankets or a sleeping bag for both mosquito protection and warmth; even in August, clear nights can become surprisingly chilly. Then, take a deep breath, be patient, and allow your eyes to adjust to the darkness.
“Because these’shooting stars’ can appear anywhere in the sky — you don’t have to look directly at the radiant to see them — the best direction to watch is usually straight up,” Diana Hannikainen added.
Faint Perseids appear as tiny, quick streaks. Occasionally, the brighter ones will sail across the sky for several seconds, leaving a trail of glowing smoke in their wake. When you see a meteor, trace its path back to its origin. If you eventually reach the constellation Perseus (as depicted in the accompanying sky chart), you have witnessed a Perseid.
Occasionally you might spot an interloper. During Perseid season, the weaker Delta Aquariid and Kappa Cygnid showers are also active, and there are always a few random, “sporadic” meteors. All of these originate in other regions of the sky. Tracing meteors back to their radiants is a fun exercise: if the tracks do not lead to Perseus, they are not Perseids!
Any light pollution or cloudiness reduces the number of visible meteors. However, the most brilliant ones shine directly through light pollution (though usually not through clouds). Indeed, a NASA analysis of all-sky images taken between 2008 and 2013 indicates that the Perseids produce the most bright meteors (those that outshine any star) of any annual meteor shower.
For the uninitiated, meteors are caused by dusty particles the size of sandgrains to peas colliding with the top of the Earth’s atmosphere approximately 80 miles (130 kilometres) up. Each Perseid flies in at a speed of 37 miles per second, glowing as it burns to soot and forming a short, white-hot streak of superheated air. Grape Nuts cereal contains nuggets that closely resemble the estimated size, colour, and texture of typical meteor-shower particles.
The Perseid fragments were ejected long ago by Comet Swift-Tuttle and are scattered throughout the comet’s orbit around the Sun. Every year in mid-August, the Earth passes through this precarious “river of rubble.” The comet is named after Lewis Swift and Horace Parnell Tuttle, who discovered it independently in July 1862.
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