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Re: (meteorobs) Re: Horizon Perseid Meteors
Bob Lunsford wrote:
> We must remember that when looking in the lower portion of the sky we
> are looking through a tremendous column of air and therefore many
> meteors will be seen there. Why not focus your view that low all the time
Sorry for the late(!) comment on this one, but I'm just getting caught
up after my Honeymoon. :( Bob is correct that when you look low, you are
viewing through a much greater volume of earth's atmosphere than if you
aim your head at the zenith. HOWEVER, you are also experiencing a much
greater atmospheric and distance extinction! Surprisingly (according to
some calculations done by Rainer Arlt of the IMO, if I recall correctly)
these two effects actually nearly cancel each other out!
As a result, you probably will NOT see more meteors by keeping your FOV
down to the horizon: still as Bob suggests, I keep my own CFV (Center of
Field of View) generally at about 70o elevation... That just seems like
a good spot in the sky generally, even for us narrower FOV-type folks. :)
BTW, thanks to Malcolm for pointing out the depenence of apparent speed
on meteor elevation, too: it's nice to see hard numbers posted on this!
Clear skies folks,
Lew
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