[Prev][Next][Index][Thread]
(meteorobs) Re: Where to look for LM Counting Areas
-- [ From: Robert Lunsford * EMC.Ver #2.5.3 ] --
Lew, You Wrote:
> In fact, according to discussions on meteorobs last year, the
"standard" IMO
> method (and so possibly the one used by the majority of observers here
?) is
> actually the first! I began by using LM count areas SCATTERED around
the sky,
> with the idea that these would average out any variations in LM across
the sky
> due to high atmosphere haze, light pollution domes, twilight, etc. But
I was
> quickly corrected by more experienced readers of meteorobs, that IMO
LM count
> areas should in fact be chosen as close to the ZENITH as possible! So
how about
> it, guys: is this the method used by most IMO observers now?
>
Lew, this is possible but it is totally incorrect. One should always use
the two counts areas closest to your center of view when making limiting
magnitude estimates. Does it make sense to estimate the LM of the zenith
when you are viewing the sky only halfway up? One need to estimate the
LM of the area they are viewing. Besides, viewing directly at the zenith
is not recommended since this is the area where the least activity will
be seen. This is due to the fact that when looking straight upward you
are looking though the thinnest column of atmosphere and the shortest
distance through the atmosphere. Looking at angles less than 90 degrees
provides a larger slice of atmosphere therefore providing more
opportunity to see meteors. Most of the meteor activity actually occurs
near the horizon but I would not suggest looking there since nearly half
of your view will be obscured by the ground. This is why it is suggested
that an observer look just high enough so that the bottom of their
vision lies on the horizon.
Bob