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From: TerryMoselaol.com
Date: Sat, 7 Aug 2004 14:32:01 EDT
Subject: Plenty of Perseids

Hi all,

Maximum of the Perseids meteor shower approaches, and conditions this year 
are very favourable, with no moonlight to worry about.

Some are already being seen each clear night, but the best is yet to come. 
They will increase in number each night for the next couple of days, reaching a 
maximum late on the night of 11/12 August, when up to 100 meteors per hour may 
be visible under good conditions!

There's already quite a lot of media interest: - I've already been 
interviewed on Radio Ulster, Evening Extra, & Belfast City Beat, and I'll be on Downtown 
'Margie's Magazine' on Sunday (2-3 p.m.), and on Cool FM (Johny Hero) on 
Monday morning about 10.40. So this could be a good chance to promote astronomy & 
the IAA etc if the public ask you about the Perseids.

This shower occurs when the Earth passes through the trail of particles given 
off by Comet Swift-Tuttle, named after its discoverers.

A meteor is just the fiery death of one of these particles, which we see as 
it burns away during its high speed impact with our upper atmosphere. Most are 
just the size of a sand grain, brighter ones can be as big as a grape seed or 
apple pip, and a really bright one would be only the size of a pea! So we 
don't see the particle itself, just the fiery trail as it burns away at a 
collision speed of about 60 miles per second!

The Perseids are always one of the best annual showers, and with conditions 
this year being particularly favourable, let's hope for clear skies. Some 
experts also think that activity will be unusually high this year, and we may also 
get an extra early burst of activity just as darkness falls on Wed 11th. This 
is expected as we may pass through a dense 'filament' of particles given off 
by the comet at its penultimate perihelion passage in 1862. This is predicted 
for 21.50 BST, so we might just get the end of it as the sky darkens.

Activity should be quite high on the nights of 10/11, 11/12, and 12/13 
August, with best rates in the early hours of 12 August, and the possible early 
burst of activity early on the previous evening. Perseids can appear in any part 
of the sky, but if you trace their paths back they will appear to come from 
Northern Perseus, which will be rising in the North East in the early evenings, 
getting high up in the Southern part of the sky just before dawn. The radiant 
moves slowly across the sky during August, and on the night of maximum it lies 
not far from the 'Double Cluster' in Perseus, or about 5 degrees N of Alpha 
Persei.

You'll see most meteors by looking at an altitude of about 50 degrees, and 
about 45 degrees to either side of the radiant, on whichever side the sky 
appears darker. But to get a proper view you must get away from all light pollution. 
If there's a lot of artificial light nearby, you might see only about one 
tenth as many meteors as if you were out in a dark rural sky. 

So, if it's clear next Wednesday night, or even the nights before and after, 
have a look at the sky for as long as you can, and see some of these tiny 
visitors from space end their lives in such a spectacular fashion!

Clear Skies,

Terry Moseley


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