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Re: Meteor Velocities
I need to clear up a few items that pertain to my last note. First of
all it is true that measurements of velocity are used solely for
shower identification. The NAMN scale of 1-5 is satisfactory in
almost every respect. I do feel though that it is inaccurate for
radiants of low altitude. This is not a major setback since most
observers watch when the radiant is high in sky. I would heartily
endorse this method of estimating velocities to all newcomers to the
field. It definitely was not my intention to make a simple category
too complicated. If it was not for the 94 Aurigids I would still be
using this method today. I just feel that estimating in degrees per
second gives a more accurate velocity estimate in any situation.
Personally, I have never seen a meteor last longer than 5 seconds. 15
seconds for a rating of 1 seems a bit extreme. I totally agree with
George that velocity alone does not determine whether a meteor is a
shower member.
Estimating durations in 1/5 second increments is not difficult for
the experienced observer. The AMS states that observers should
distinguish down to 1/10 second, which is pushing things a bit too
far beyond the scope of reality.
I urge all new meteor observers to use the NAMN velocity scale. When
you have gained experience then perhaps you can begin estimating
durations and lengths and then employ the IMO method.
The most important thing to remember is not to make observing a chore.
It is suppose to be a relaxing and enjoyable experience. That is the
bottom line.
Bob Lunsford