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Re: (meteorobs) Re: Angular velocities




me>> For what purpose 
>other than shower association is visual meteor speed estimates used for?  I 
>can't think of any.
>....  All you need to be is accurate enough to provide for adequate 
>shower association. You don't need to measure anything or estimate any 
>durations or do any kind of math in your head....just record the speed 
>impression you get from Slow to Very Fast and have some rough sense of the 
>meteor's distance from radiant and know what it means.<<

norman>>I'll drink to that .... as long as it's fresh cow's milk, being a
teetotaler.  As you become familiar with each major shower, you learn what
meteors of various true velocities look like.  Then you will know similar
velocities when sporadic meteors appear.  It does become second-nature with
experience.<<

I'm a teetotaler too....but Milk.....Uuuck!  :o) I only like milk in 
cereal...which i eat a lot of. I'll toast you with diet cherry 7 up though. 
Still trying to lose a few more pounds that has crept up these last several 
years.  Lost 16 pounds this year already....trying for another 10 by Fall and 
I will be where I want to be. Hopefully this will help me during the next 2 
years at work?

norman>>With these two quantities recorded, then if I wanted to know the 
velocity in
degrees per second, it is just a matter of doing the arithmetic at leisure.
In fact, I have never desired to do it.  As far as recording this data goes,
I discontinued these items after the summer of 1976 as no new information
was coming from it, and I wanted to streamline field work.  Around 40000
meteors had been recorded by that time anyway.<<

This is pretty much what I've been trying to say or advocate. 

norman>>Perceptions of distance and duration do vary between observers.  <<

Yes, a well noticed fact is obvious when you look at the plots of relative 
beginners or even infrequent plotters over a course of years.....their 
plotted distances of meteors onto charts are often very long....too long for 
what is really happening. This error is normal since the travel of a meteor 
appears in a straight line. The observer will instinctively follow this path 
with their eyes and unconsciously project it longer. Eventually plotters will 
recognize this illusion thru experience and make the necessary corrections, 
although they may still not perceive anything different.

norman>>Olivier was struck by the shortness of my plots from the beginning.  
<<

Perhaps because Olivier was aware of this illusion and was trying to make 
some sense out of it?
 
norman>>Bob's sense of time must run a lot slower than mine.  I would have
thought that training with a watch would not permit such a large difference,
but now  that's out the window.<<

I think so to....in the past, bob would often say he will be at the 
observatory at 1 am and end up getting there around 2 am.  :o)

 norman>>For meteor speeds my goal these days
is estimating true velocity within 3 categories : slow, medium, fast.  I am
not concerned with just the angular velocity.  I take the distance and
duration  under consideration together to come up with a speed class.  It
becomes second-nature with experience.  This information weeds out an
occasional meteor from a known radiant that doesn't have the proper speed.
It also weeds out meteors from new radiants that don't fit the majority
profile ; if most of the meteors from a developing radiant are fast, I would
drop any slow meteor from the same radiant, for example.<<

Except for breaking meteors down intially into 5 categories, the method I use 
essentially allows meteor classification that end up being Slow, Medium and 
Fast. After reading closely what you are saying here, I think you and I are 
doing the same thing? It becomes second nature with experience and is good 
enough for the purpose the information will be used for.
GeoZay
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