(meteorobs) Re: Determining if a meteor is part of the shower

[Robert Lunsford]

Al and All,

Shower meteors can appear in any portion of the sky. The main determining 
factor on whether they are Eta Aquarids or not is if their path lines up 
with the radiant in Aquarius. Eta Aquarid meteors will appear to shoot from 
the radiant area in Aquarius, therefore those moving west to east cannot 
possibly be Eta Aquarids. Most Eta Aquarid meteors will appear swift and 
will be gone in an instant. This is caused by the fact that they are 
striking the Earth in a head-on direction. Eta Aquarid meteors seen close to 
the radiant will appear to move more slowly as they are approaching the 
observer. Their path lengths will also be shorter than those seen far from 
Aquarius. Aquarids seen low in the sky will also be shorter and slower as 
they are moving away from the observer. Eta Aquarid meteors are also notable 
for producing a high percentage of persistent trains. These trains are made 
up of ionized gas and appear as smoke-like streaks for a short time after 
the meteor has vaporized.

Hopefully these clues will help you distinguish between meteors during your 
next session. For those new to meteor observing, it is often difficult to 
distinguish their path as they last on the order of one half second. A 
useful tool to use to help determine the path direction is a dark, thick 
cord approximately three feet long. A shoelace is a perfect example. While 
you are waiting have the cordtips in each hand and then extend it over the 
path of the meteor once it is seen. If the meteor was moving away from 
Aquarius and cord then lines up with the radiant area in Aquarius then it's 
a good chance you jut saw a true Eta Aquarid.  By the way, the radiant area 
is located near the "Y" shaped group of dim stars located in north-central 
Aquarius. You can find out more about observing meteors from the following 
web sites:

http://skyandtelescope.com/observing/objects/meteors/article_98_1.asp
http://www.amsmeteors.org/
http://www.namnmeteors.org/
http://www.meteorobs.org/
http://www.imo.net/

Clear Skies!

Robert Lunsford


----- Original Message ----- 
From: "Al - Sky Insight" <Al.Degutis at gmail.com>
To: <meteorobs at meteorobs.org>
Sent: Wednesday, May 04, 2005 8:57 AM
Subject: (meteorobs) Determining if a meteor is part of the shower


I've just started observing meteors. This morning (03:00 CDT) I was
out for about an hour in hopes of seeing some Eta Aquarids. At my
latitude (42°N) Aquarius doesn't get above the horizon before 3am. I
spotted 7 meteors between 03:30-04:30 but I'm not sure if any were
part of the shower or if all were just sporadic. None of them were in
the east. The closest one were in or around Cygnus and the rest a
little south and a bit north near Draco.

About half traveled from west to east and those may have been Aquarids
but the others traveled east to west. I'll be out again the next two
mornigs but how do I determine which ones are part of the shower and
which are not?

Thanks
Al Degutis


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