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
aol.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
