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Re: meteor velocities
Lew Gramer asked:
>You make a good point about using steps of 5 deg/s instead of the simple 0-5
>scale: by the way, *is* this roughly what is intended by the NAMN 0-5 scale,
>Mark? In other words, does NAMN approve the following (approximate) table:
>
> NAMN scale deg/s
> ---------- -----
> 0 ~0
> 1 5
> 2 10
> 3 15
> 4 20
> 5 25 & up
In short, no. :)
The NAMN scale is not, and was not intended to be, compatible with the
technique of estimating velocity by degrees/sec as the IMO does, or for that
matter, the way Bob Lunsford desribes.
Instead, it was meant as an introduction to this idea for those people
carrying out their very first observations without having to introduce
concepts such as geocentric velocity, meteor heights, radiant distances,
etc. Beginning observers are encouraged to carry out visual counts first,
paying particular attention to magnitude, time, path length and path
direction. Velocity is to be indicated with the arbitrary 0 to 5 scale as an
*estimate* of the speed (which means this estimate cannot be used for shower
association), from 0 (stationary, or almost so) to 5 (very fast).
Once a new observer begins experimenting with plotting, we request observers
to send their initial plots to us for review. This is the point at which the
IMO method of velocity estimates should be first introduced.
As a result of the types of questions we field from observers, we thought
this the best approach to provide guidance to new observers. The experienced
members we have, such as yourself Lew, were already using either the IMO or
Lunsford technique when NAMN was established.
Hope this helps, and doesn't confuse the situation. ;)
mark