Near-ground turbulence profiles from lunar scintillometer

Abstract

A simple and inexpensive six-channel array of photodiodes, LuSci, can measure weak moonlight scintillation produced by optical turbulence within few hundred metres above the ground. We describe the instrument, its operation and data reduction. Measured covariances of lunar scintillation are fitted to a smooth turbulence profile model with few parameters. Complete recipe for calculating the instrument response (including the effects of Moon's phases) is given. The robustness of the results relative to various experimental factors and model assumptions is investigated. We give examples of the data and compare LuSci with other turbulence profilers. LuSci finds numerous applications in nighttime site testing and monitoring.