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Analysis of the Distribution in time.
I analyzed the distribution in time of papers and publications included in the
Reference List - Part A (version 2: August 4, 1994). Even if the sample is far from
being complete, I think that it collects almost all the important papers and the most
cited publications. I belive that the trend of the number of entries can be considered, in
first approximation, a quite good index of the trend of the interest for the light
The number of entries for year in the Reference List, show some peacks in 1973, 1984
and 1991. The first peack corresponds to the first burst of interest for the Light
Pollution which is connected to the more general interest for Site Protection growed in
these years when the International Astronomical Union (IAU) created the Commission 50 (The
protection of Existing and Potential Observatory Sites). The peack in 1984 may be the
delayed result of the impulse given by the IAU which in 1979 had published the Recomandations
of Commission 50 (Smith 1979) and in 1980, in collaboration with the Commission
Internationale de l'Eclairage (CIE), the Guide lines for minimizing Urban Sky Glow
near Astronomical Observatories(Cayrel 1980). The peack in 1991 is mainly produced by
the publication of the Proceedings of the IAU Colloquium 112 ( Light Pollution, Radio
Interference and Space Debris) held in 1988.
The logarithm of the mean number of entries for a year averaged over five years
increase approximately linearly with approximately a derivate of 0.076. Then the mean
number of entries, rapidly increasing from the seventies to date with an increasing
derivative, can be well expressed by an exponential.