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(meteorobs) Perception coefficient



I was not able to follow the discussion about the perception coeffient, but will
try to explain what we mean.

It turns out that some observers have a better perception for moving objects
than for steady ones. Hence they will see too many meteors considering the
limiting magnitude. Others are better able to spot faint stars but miss a lot of
faint meteors. The perception coefficient compensates these effects.

How is the perception coefficient calculated? A large data set should be
available. Then the mean ZHR will be very close to the 'true' ZHR which an
observer with equal meteor and star limiting magnitudes would get. If an
observer systematically deviates from the mean he gets a perception correcetion
which is larger than 1.0 if he sees too many meteors. The perception can be
expressed in a delta-lm which is the change of star limiting magnitude he would
need to compensate his ZHR values. In an ideal case one observer gets about the
same cP or delta-lm in different analyses. Otherwise it is questionable if his
lower or higher rates are systematic.

The perception coefficients have nothing in common with perception probabilities
which define the probability to see a meteor of a certain magnitude. Perception
probabilities are use to calculate population indices (and mass indices) of
meteor showers. The perception probability is a function of the difference to
the limiting magnitude. Meteors one mag brighter than lm have a lower
probability to be detected than a meteor two mags brighter than lm.

Rainer