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(meteorobs) Do eyes work at all?
I have been analyzing the results of my Perseid observations for the last
three days and I have obtained some disturbing results.
The observational setup was as follows: eighteen butterfly chairs were set
up, with four facing north, four northwest, four west, and four southwest.
(This arrangement insured that nobody had the moon in their direct field of
view.) The chairs incline the body such that you face an altitude of about
50 degrees. Whenever an observer saw a meteor, he pressed a button, and the
time of the button-press was recorded to a tenth of a second. The computer
equipment all worked flawlessly. A total of 360 distinct meteors were
counted during a 2h 45m period from 1:45 local time to 4:30 local time. This
leads to a cumulative observed rate of 132/hour. Now, before you laugh out
loud, remember, this is a cumulative rate for all observers. Indeed, the
average individual rate was around 25 - 30 per hour, in line with what
others reported.
Here's the disturbing part: half of the observed meteors were reported by
less than two observers (note carefully tricky wording). The average
observer saw only about 25% of the meteors that the group as a whole saw
(average rate over cumulative rate). This is buttressed by the Opik
calculations I did with one group, the west-facing group of four. These
people got coefficients of perception of 0.14, 0.25, 0.24, and 0.23. A
completely different calculation for the group as a whole yielded similar
results.
Now, there are plenty of serious objections that can be raised to this data.
The first is that the observers were all utterly green civilians who had
never seen a meteor before. Clearly such people can't give reliable data,
and clearly, the data obtained from experienced observers will be better.
But, how do we know that data obtained from experienced observers will be
better? Sure, we believe it, and sure, it only stands to reason, but given
the abysmal results from this group, even if old pros are twice as good,
they're still pretty bad.
So the question I put to this group is, what do we know about typical or
normal coefficients of perception?
Chris
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