For anyone planning to watch the Perseid meteor shower this weekend, the forecast holds some bad news.
Rumors have been flying around online that we’re set for “the brightest shower in recorded human history.” But the presence of a more than half-full moon on Saturday night and Sunday morning when the event is at its height means the shower might be a little overshadowed.
What’s the problem?
Avoiding light pollution is key to watching an astronomical event like a meteor shower. A sky far out in the countryside shows more details than one bathed in the glow of a city.
But the presence of the moon might have a similar effect. "To be honest, it's not a good year" for the Perseid shower, said Robert Massey, acting executive director of the Royal Astronomical Society (RAS) in London. "You might, if you're lucky, see maybe 20 an hour," he told AFP.
The moon was full on August 7, so by Saturday, August 12, it will have waned to about 80 percent illumination. According to Sky and Telescope magazine, the brightness of the sky overhead at full moon away from an urban center can be the same as an urban center on a moonless night. Saturday won’t be quite that bad, but 80 percent isn’t too far off.
So is there any point watching?
Yes. Especially if you time things carefully, say meteor experts (or meteoriticists, to give them their proper name.)
According to the International Meteor Organization (IMO), catching the shower early on is an easy fix. If you watch before 11:00 pm, when the moon rises, you might get a more uninterrupted view.
The meteors will be sparser around at that time but, the IMO says, "these meteors tend to be very long and long-lasting so it is definitely worth trying to see some of them."
It’s also a good idea to check the weather forecast. Try and watch when there’s a clear sky in your part of the world; if it’s a very cloudless night, that plays in your favor.
What are the Perseids anyway?
Active from July 17 to August 24, the Perseids are particles released from a comet named 109P/Swift-Tuttle, flying off its tail as it journeys deep into the inner solar system.
Every year, the best time to watch the shower of particles is August 12 or 13. In a normal year you might see 50-75 meteors per hour in a rural location.
The name comes from their location. When the shower is at its height and most visible from Earth, it appears to originate from the constellation of Perseus, a hero in Greek mythology for killing Medusa.