Observatory Cameras Catch Perseid Meteors

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The Perseid meteor shower, which this year peaked around midnight on the evening of August 12th, will continue at a low rate until around August 24th. The Perseid meteors, or "shooting stars", take their name from the constellation, Perseus, from which they appear to radiate, and always produce a good display. This year, the main peak of activity was marred by cloudy skies over Northern Ireland and strong moonlight, but the ObservatoryтАЩs roof-mounted meteor cameras detected more than 100 such shooting stars, with more expected over the coming days.

Video clips in AVI and mp4 formats of some of the brightest Perseid meteors detected by the ObservatoryтАЩs cameras together with an image illustrating the parallel tracks in space of the Perseid meteors detected at Armagh can be found here. More meteor detections can be found here.

Those who wish to see a shooting star should select a clear, dark observing site with as little moonlight or artificial light pollution as possible. During August, soon after dark, the constellation Perseus can be seen rising low in the north-east. Although Perseid meteors will appear to originate from this general direction, known as the radiant, the actual shooting star can be seen in any part of the sky. For example, you may look at an angle of about 45 degrees away from the radiant, perhaps overhead or towards the north or east, whilst keeping the radiant near the edge of your field of view. If possible, look away from any nearby light pollution.

Always allow time for your eyes to become accustomed to the dark, and expect to wait 20 or 30 minutes before seeing your first meteor. To avoid fatique, wrap up warm and recline in a comfortable chair under a rug or sleeping bag to avoid the cold. Take time to enjoy your view of the dark, night sky.

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Most meteors are produced by comets, which shed trails of dust while passing through the inner solar system on their elliptical orbits around the Sun. In the case of the Perseids, the Earth encounters this material at a relative velocity of more than 200,000 kilometres per hour. This causes the small cometary dust grains, which have sizes ranging from typically a few millimetres or less up to a centimetre or more, to vaporize at a height of around 100 kilometres as they collide with molecules in the very tenuous region of the EarthтАЩs upper atmosphere known as the mesosphere. It is this vaporization, or burning up, of dust in the EarthтАЩs atmosphere that produces the visible streak of light called a meteor.

The parent comet of the Perseids, namely Comet 109P/Swift-Tuttle, last passed through the inner planetary system more than 20 years ago in 1992 and will not return until 2126. Nevertheless, the Perseids are a very old meteor shower, having been recorded over nearly 2000 years, and the number of visible meteors from the comet remains at a high level. The level of activity shows no sign of diminishing from one year to the next.

Further video clips of bright meteors, called "fireballs", can be viewed on the Network for Meteor Triangulation and Orbit Determination website

For more information contact Mark Bailey or Apostolos Christou at the Armagh Observatory, College Hill, Armagh, BT61 9DG. Tel.: 028-3752-2928; FAX: 028-3752-7174; mebarm.ac.uk or aacarm.ac.uk.

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Last Revised: 2014 August 15th