Astronomy Picture of the Day

Explanation: From a radiant point in the constellation of Perseus, Comet Swift-Tuttle presents -- The Perseid Meteor Shower -- coming to your night sky this weekend! A bookish E. C. Herrick of New Haven, Connecticut correctly suspected in 1837 that this meteor shower was an annual event. Indeed it is now known to be a regular August shower caused by the yearly passage of the Earth through the orbiting debri left behind by periodic comet Swift-Tuttle. Since the bits of comet debri are moving along parallel orbits, on entering the atmosphere they leave fiery trails which appear to originate from a common radiant point in the sky, in this case in the constellation of Perseus. Dramatically illustrated in this composite video image made using MOVIE, meteors from the 1994 Perseids streak across the sky framed by the three bright stars of the asterism known as the "Summer Triangle". The image shows bright Perseids recorded that year from August 9 through 14. Here the trails appear nearly parallel as the camera was centred on the sky about 90 degrees from the radiant point. This year, European and North American observers should be able to view the shower near its maximum, about 90 meteors per hour, early Monday morning August 12, but the shower should be enjoyable on clear weekend nights (August 10,11) as well. After midnight is generally the best time for viewing. What's the best way to enjoy a meteor shower? Get a warm jacket and a comfortable lawnchair ... go outside and look up.