[meteorite-list] Re: Green Glow Over North Carolina Could Have Been Meteor Shower

From: Marco Langbroek <marco.langbroek_at_meteoritecentral.com>
Date: Thu Apr 22 10:28:35 2004
Message-ID: <007b01c39a16$b8e8fa20$8cc3ea3e_at_HAL>

Message: 7
From: "Bob Martino" <martino.6_at_osu.edu>
Subject: [meteorite-list] Re: Green Glow Over North Carolina Could Have Been
Meteor Shower

>> Orionids at 8:45 pm??? No way! The radiant is far below the horizon then.
>
> Sorry, but this isn't correct.
>
> One can indeed see meteors from a shower when the radiant is below the
> horizon. Meteors do not cluster at the radiant point, but rather appear
all
> over the sky.

Sorry Bob, but you are mistaken.

Meteors from a given radiant are only visible if the radiant is above the
horizon from that location too. Yes, meteors are visible all over the sky;
but only if the radiant is above the horizon.

And at 8:45 pm, the Orionid radiant isn't.

With the radiant still below the horizon, the earth itself is between you
and any stream meteors entering atmosphere. This means your piece of
atmosphere is shielded from incoming stream meteors at that moment. Only
when the radiant appears over the horizon, meteors from this radiant start
to graze through the atmosphere above you.

Orionids are only visible in the second part of the night. By contrast, the
Taurid stream can be seen in the evening too, because the radiant(s) rise
earlier.

- Marco Langbroek
  Dutch Meteor Society (DMS)


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Dr Marco Langbroek

marco.langbroek_at_wanadoo.nl
meteorites_at_dmsweb.org
http://home.wanadoo.nl/marco.langbroek

"What seest thou else
 In the dark backward and abysm of time?"

                            William Shakespeare
                            The Tempest act I scene 2
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Received on Fri 24 Oct 2003 06:03:36 AM PDT