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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 pollution problem.

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.