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Re: (meteorobs) Observer perception (long!)
Hey, Adam, great question! Again, there are more expert folks on the list
who I hope will follow-up on this thread, but here's my try...
Yup, I've definitely seen what your group observed: X people all observing
in the same direction on the same night under the same sky, will have X
different rates - i.e. will all see different numbers of meteors over the
same time.
Part of this difference is accounted for by the scatter of "LMs" -
"Limiting Magnitudes" - among different observers. Since you've been
observing for a while, you probably already know LM is just the magnitude
(brightness) of the faintest star a given observer can see at a particular
moment, at the zenith. Two different observers' LMs may differ by as much
as a magnitude or more under identical conditions. And of course the
fainter the stars you can see, the fainter (and more) meteors you can see.
But apparently there's even more to it than that! Even when observers have
the same LM, they can often report radically different simultaneous rates -
some times differing by a factor or 2 or more! A variety of factors have
been suggested to account for this:
o Directions observers face may obviously make a difference. Some folks say
looking X degrees off an active radiant may increase rates; others say
looking SW may; and some say this will depend on time of year and shower.
But if all observers have the same "center of field", this shouldn't be a
factor.
o Differing "fields of view" for different observers' eyes. Some observers
seem to see most of their meteors within about 10o of wherever their head
happens to be aimed. Others see a fair number even 50o or 70o out.
o Differing responses to transient light phenomena. No one (I know of) has
talked about this one, but it sure could explain some differences.
As for how you figure a "perception coefficient" which takes into account
particular observers' sensitivity, Peter Jenniskens has written some papers
describing approaches. Also, the topic has been discussed in the
International Meteor Organization journal "WGN": can some folks summarize
the gist here?
Lew