From: TerryMosel@aol.com
Date: Fri, 9 Aug 2002 17:22:46 EDT
Subject: POURING PERSEIDS...

Hi all,

We are just coming to the best few days for the Perseids, the second best of 
the regular meteor showers (beaten only by the Geminids, but they occur in 
cold & frosty December). So this is the shower for meteor observing wimps.... 
And there's no interference from moonlight, so make the best of any clear 
skies!

But seriously, weather permitting, you can spend a very pleasant late summer 
evening watching Perseids, in a nice dark sky, with only a bit of extra 
protection from the falling temperature. A jersey, anorak, hat, and a lounger 
are usually the only extras you need, unless there's a cold wind blowing, or 
you're on a mountain top.

PERSEID MAXIMUM is predicted for JUST BEFORE LOCAL MIDNIGHT ON MONDAY, but 
the activity level is already increasing, and you can see quite good numbers 
of meteors on any night from now until Wednesday night.

Observed meteor rates increase dramatically with radiant altitude, so even 
though it's very close to maximum as darkness falls on Monday evening, rates 
won't start to get high until about local midnight, and the highest observed 
rates will probably be in the small hours of Tuesday morning.

The night before maximum (Sunday night) will probably be quite good also, 
especially from midnight until dawn, and the night after max (Tuesday night) 
should be good too, although rates drop off more sharply after maximum than 
they rise before it.

You will see most meteors if you look about 45 degrees on either side of the 
radiant (which is in N Perseus - say roughly between Perseus and Cassiopeia), 
and about 50 degrees above the horizon (roughly the altitude of Polaris). If 
you have a choice on either side, look in the direction where the sky is 
darkest and clearest. 

It goes without saying (I hope) that you will see many more meteors from a 
dark sky site, than from a city! So if the sky is clear, it's worth driving a 
few miles, or tens of miles, to get a really dark location. If you have local 
light pollution only, try to position yourself so that the light is hidden 
from your eyes.

Perseids are quite fast meteors, though not as fast as the Leonids, and there 
are usually some quite bright ones (brighter than Vega), and a few fireballs 
(brighter than Venus). You may also see a few sporadic meteors, or members of 
other minor showers, but unless you are a meteor afficionado you can just 
count all the others as 'non-Perseids'.

Allow about 10 minutes for your eyes to dark-adapt reasonably, although full 
dark adaptation takes 20-30 minutes. Don't use a white torch or you'll ruin 
your dark-adaptation for quite a while; use a red one instead, e.g. a bicycle 
rear lamp, or cover the lens of an ordinary torch with red polythene. 
Sometimes a shop's plastic bag will be at least partly red, so just cut out a 
red bit & tape it over the front.

(IAA members have already been notified about our 'Perseids BBQ' on the first 
clear night of either Sunday, Monday, or Tuesday...)

Good Luck, Clear Skies, and send in all your observations, if you get any!

Terry Moseley

Last Revised: 2002 August 12th WWW contact: webmaster@star.arm.ac.uk

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