Re: [APML] Meteor Showers and Their Radiant

["Kevin Wigell" <kwemail@twcny.rr.com>]

Think of the earth as a sphere in space traveling through a swarm of tiny 
rocks or grains of sand coming from one direction. They will only hit one 
side of the earth at a time. If you are on the side of the earth facing away 
from the direction the swarm is coming from (which means the radiant is 
below the horizon for you), you will not see any meteors caused by that 
swarm. If your are on the side of the earth facing toward the direction the 
swarm is coming from (which means the radiant is above the horizon for you), 
you will see meteors caused by that swarm or meteor shower. If you are on 
the earth right on the borderline between the two, that means the radiant is 
either just rising or setting for you. In that case, you will see 
"skimmers", i.e., meteors that are just skimming through the earth's 
atmosphere. For you, they will tend to appear to follow parallel paths 
coming from the direction of the radiant and possibly shoot all the way 
across the sky.

So you generally can't see meteors unless the radiant is above your horizon 
or at least very close to it. Otherwise, the earth itself is blocking those 
meteors.

Of course, the real situation is much more complicated, because the earth is 
constantly being bombarded by little grains of sand from all directions. But 
the above is true for any given meteor shower swarm.

Kevin Wigell

----- Original Message ----- 
From: "Alan Voetsch" <alanv12952@yahoo.com>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Monday, June 06, 2005 12:18
Subject: Re: [APML] Meteor Showers and Their Radiant


> Hey Wade,
>
> --- "Thomas W. Earle" <twade@bmi.net> wrote:
>> around 3 AM.  Is it necessary for a meteor showers radiant to be
>> above the horizon to see an associated meteor?  Logic would suggest
>> the answer is NO since the meteor could stream westward from the
>> radiant thereby becoming visible before the radiant rises.  Is this
>> correct?
>
> Well, logic tells me to ask this question; how far away from the
> radiant can you see meteors during the night? The answer is; you can
> see them all over the sky. Unless I am badly mistaken (again), it will
> not be necessary for the radiant to be above the horizon.
>
> Alan
>
>
> SCT Astrophotography: http://www.pbase.com/avoetsch/astrophotography
> FS-102 G-11/Gemini: http://www.pbase.com/avoetsch12952/tak_fs102
> & http://www.pbase.com/avoetsch12952/fs102
> & http://www.pbase.com/avoetsch12952/takpf
>
> 


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