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Re: (meteorobs) Limiting magnitude question
Quoting KevTK@aol.com:
> Two different people can get 2 different
> LM's from the same area. I often observe with W. Hally and my skies are
> typically darker than his, and we are just sitting 10ft. away or less from
> each other. Yes, it's subjective, but thats just the nature of the beast.
Limiting magnitudes are indeed very personal. This is partly due to biologic
differences between individuals (although differences in estimating technique
also play a role, e.g. there will be a difference when one person uses averted
vision while the other counts with the center of his view while counting stars
in one of the Lm areas). "The" limiting magnitude is not a fixed entity for a
given location and sky condition because it is not only sky quality but also
individual "quality" (wrong word, but don't know how top say it else) with
regard to dark vision involved. My dark vision is for example better than for
many other persons, which results in not only deeper Lm's while observing, but
for example also a better ability to move around a dark environment as I
recently noted during a campaign where one of my fellow observers couldn't see
anything and almost stumbled over obstacles etc. which I could clearly see.
Indeed, he always has lower Lm's too, so that's at least consistent.
From my experience by the way, when skies become really dark and Lm's go up
above +7.0 there are too many stars in most Lm count areas to properly count
and this becomes a problem. Well, with such Lm's, correction factors on a ZHR
calculation become very large and thus troublesome anyway so if you want usable
meteor data you actually shouldn't go to a spot with sky-high Lm's.... (that
is: Lm clearly above +7.0). This is a point often forgotten: from the
standpoint of meteor data reduction, a very high Lm is as bad as a very low Lm.
So, dear meteor friends: find yourselve a locality where your Lm is good enough
for enjoyable rates and nice starry skies, but not too good...! From that
perspective, no reason to be jealous of +8.0 skies reported.
- Marco
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