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(meteorobs) FWD from P Jenniskens: Perception Coefficient
Forwarded with permission based on a personal email from Dr. Jenniskens.
Note in particular his use of DCV in calculating the coefficient...
Enjoy!
Lew
------- Forwarded Message
Date: Tue, 3 Sep 1996 12:39:31 -0700
From: peter@max.arc.nasadot gov (Peter Jenniskens)
To: dedalus@latradedot com
Dear Lew,
You asked about perception coefficients. In my analysis of meteor stream
rates, I have used the observed sporadic rates at 0h UT during the Perseid
campaign to normalise the meteor stream rates. I adopted that a standard
observer sees 10 sporadic meteors per hour at that time of night and day of
the year. The perception may vary during the year, in which case I sometimes
use the observed sporadic rate at other times of night or days of the year
to estimate the observer perception (taking into account the diurnal and
annual variations).
It is possible however to measure the observer perception by determining
the observer's probability function (that is, the percentage of all meteors on
the sky of a given magnitude seen by an observer). The probability function
can be determined by keeping a record of the distance of center of vision
(in degrees) of each meteor seen. The method assumes that the magnitude
distribution of meteors is constant over the sky and the number is constant,
hence it is only an approximation! The method is as follows: take all meteors
oberved with a dcv of 20 degree or less. Make a plot of the logarithm of
the number versus magnitude. The slope of bright meteor should be equal
to the magnitude distribution index. The faint meteors can already be missed
to some extend within this region. Then: after knowing the number of bright
meteors within the 20 degree region, it is possible to calculate the number
of bright meteors that should have been seen over the whole sky. The
fraction of actually observed meteors gives the probability for that
magnitude.
Hope that this is of some help to you. Some explanation is given in
A&A paper I on meteor stram activity. If you don't have a copy yet, I
am happy to send an offprint.
Greetings,
Peter.
u