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Re: (meteorobs) meteor duration estimates

In a message dated 96-10-30 02:57:54 EST, Norman write:

>
>Meteor durations can only be judged by how they appeared.  This is the sense
>of short intervals that you only develop through practice.  I trained by
>visualizing meteors while watching a second hand on a watch.  Jim's
>technique sounds good, too.  George, Jim didn't mean using the stopwatch in
>actual timings, just developing his sense of timing.<<<

Norm, it seems that you judge a meteors duration the same way I judge a
meteors apparent speed...ie, the experienced sense of what it looks like...or
how fast it appeared to move. If I saw a meteor appear as a  fast moving
streak, I would identify it as a Very Fast meteor.  If you saw the same
meteor you would probably identify it from the same appearance that it lasted
about .1 to about .2 second. You already know that most meteors are  going to
travel about under 5 degrees. You now have established in your mind that a
Very fast looking meteor will have to have certain tenths of a second to make
sense and naturally bias yourself to come up with these values so that they
would make sense. The bottom line is that you are using a speed scale based
on how the meteor appeared to look by it's apparent  movement.  
>
>It took me three years to get the durations stabilized.  My first efforts
>gave Perseid meteors all 1 to 2 seconds, obviously grossly overestimated.
>(Ever notice how the public gives fireball timings a factor of 3 to 10 times
>too large?)  As time passed my timings gradually decreased.
>
>The most numerous timing for me is 0.3s, with a fair number more at 0.2s.  I
>have very few as fast as 0.1s, and it's impossible for these to go more than
>a few degrees.<<<

Like I said, you have prior knowledge as to what's expected and adapted.
 Wouldn't it be much simpler to use a speed scale scheme and avoid all the
other convoluted processes in between? The results in the end are the same,
but the 5 speed scale scheme with the numeric 3 scale groupings is a lot
easier to use. 

George Z.