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.

The temporal behavior of atmospheric turbulence has been analyzed by means of angle-of-arrival (AA) fluctuation measurements. The temporal evolution of the main atmospheric optical parameters (AOP) have been studied in order to determine their stability. This is of interest because these AOP are necessary for the optimization of high angular resolution techniques. A new method of coherence time τ0 monitoring with the Generalized Seeing Monitor (GSM) is presented and the measurements obtained at major sites over the world are presented (La Silla, Cerro Pachon, Paranal, San Pedro Mártir, Mt Palomar, Mauna Kea, La Palma, Oukaïmeden, Maydanak).

Aims. Within the framework of site qualification for the future European large telescope E-ELT, a campaign of measurements was carried out for ten nights in December 2007 at Paranal using six independent instruments. Methods. To characterize the optical turbulence, two techniques were used: the statistical analysis of the fluctuations of the angle of arrival and the scintillation of the observed objects which are, in this case, a single star for DIMM, GSM, and MASS, a double star for Cute-SCIDAR, and Moon limb for MOSP and LuSci. Results. The optical parameters measured in this campaign and presented here are the seeing, the isoplanatic angle, the coherence time, and the outer scale. We obtain a good agreement with the value measured in previous campaigns. We also extracted the vertical profile of the turbulence given by C 2 n (h), and the profiles of the outer scale for the first time at Paranal. A comparison of the different results that we present here allows the determination of the energy distribution in the free atmosphere, on the ground layer as well as in the first meters above ground. This reveals a significant contribution of the surface layer to the degradation of the global seeing.