IAA MEDIA RELEASE
The Perseids is the best-known meteor shower of all, and this year it peaks on 12 August at about 15.00, so the nights of August 11/12 and 12/13 will be equally favourable. However, the bright Moon, not long past full, will make the sky rather bright after it rises later in the night, so try to catch the few hours between the end of twilight, and Moonrise. Although the actual number of meteors per hour decreases gradually after maximum, the fading moon, rising later each evening, means that good rates might be seen on the nights of 13/14, and even 14/15. The shower continues until 16/17 August, but rates are low by then.
Meteors are tiny particles of dust and small grains of rock that are left behind in the path of a comet as it orbits the Sun. The Perseids come from a comet called Swift-Tuttle, after its two discoverers.
We don't see the particles themselves, as they are much too small; what we see is the flash of light given off as they burn away and ionize air molecules when they collide at very high speed with the Earth's atmosphere. Most burn away at a height of about 80 - 100 km in the upper atmosphere, but bigger ones can penetrate a bit lower before finally burning up. Believe it or not, the brighter ones are only the size of a grape pip, and a really bright one would be only the size of a pea!
They can be seen in any part pf the sky, but if you trace their paths backwards, they will appear to come from the constellation Perseus, which is how they get their name. Perseus will be rising in the NE part of the sky as it gets dark, and it then gets higher and higher up as it gets later, which gives a higher number of meteors, although after the Moon rises it also gets brighter and more obtrusive. You can get an app for your phone which will show you where Perseus is at any given time.
To see the most meteors, you need to be well away from bright artificial lights, especially earlier in the night when you can enjoy darkness before the Moon rises. The best direction to look is about 40 - 50 degrees on the side of Perseus away from the Moon, and at a similar height above the horizon, as long as that's in a dark clear part of the sky. That's about half of a right-angle, as a rough guide.
Once the Moon rises, a good trick is to position yourself so that it's hidden behind a building, wall or tree, so it's not in your direct field of view.
Meteors are best seen with the naked eye - even binoculars have much too small a field of view, as you never know where the next one will appear! Use a lounger or a reclining chair for comfort, and allow at least 10 minutes for your eyes to adjust to the dark before you can see any but the brightest ones.
You can try to get photos with a phone camera, but it's a matter of luck - the meteor will be gone before you can press the shutter! So just prop the camera up pointing at the sky, in night mode, and set it to take a series of exposures each as long as possible, and hope for the best - but you'll be lucky to image even one. The best advice is - just look, and enjoy the free show.
Use a lounger or reclining chair so that you can view the sky comfortably for long periods.
Under good conditions, we might see about 100 Perseids per hour, but with the intrusive moonlight this year you might only see about 50 per hour at the best times.
The weather forecast is moderately good for those nights, so hope for clear skies!
For more information see: www.irishastro.org
NOTES TO EDITORS:
1. The Irish Astronomical Association is a registered charity dedicated to promoting interest in, and information about, astronomy and space and related topics. It is the oldest and largest astronomical society based in N. Ireland, and the largest amateur astronomy society in Ireland.
2. There is absolutely no danger, as even the biggest of these meteors burn up more than 50km up in our atmosphere.
3. The IAA runs public events throughout the year, including free public lectures at QUB, and public outreach events in various locations throughout Northern Ireland, details of which are available on the website: www.irishastro.org
Terry Moseley
PR Officer
Irish Astronomical Association
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