We describe the features of the stereoscopic approach in the imaging atmospheric Cherenkov technique, and discuss the performance of future low threshold telescope arrays.

A dust transport scheme has been developed for a general circulation model of the Martian atmosphere. This enables radiatively active dust transport, with the atmospheric state responding to changes in the dust distribution via atmospheric heating, as well as dust transport being determined by atmospheric conditions. The scheme includes dust lifting, advection by model winds, atmospheric mixing...

Recently there has been increased interest in threats to spacecraft from ground-based lasers. It has been suggested that some spacecraft should use laser-threat-warning receivers. We consider the effects of atmospheric turbulence on threshold detection of optical signals by an exoatmospheric receiver. The results are applicable to both cw and pulsed optical illumination that results from ground...

The optimum detection threshold in an on-off binary optical communications system operating in the presence of atmospheric turbulence has been investigated assuming a Poisson detection process and log normal scintillation. The dependence of the probability of bit error on log amplitude variance and received signal strength has been analyzed, and semi-emperical relationships to predict the optim...

The trajectory of a primary γ-ray detected with an array of at least four atmospheric Cherenkov imaging telescopes can be reconstructed from the shower image centroid positions and geometrical considerations independent of the primary energy. Using only the image centroid positions some cosmic-ray discrimination is also possible. This minimal approach opens the possibility of pushing the analys...

The recently derived theoretical threshold function associated with the autoconversion process is generalized to account for the effect of the relative dispersion of the cloud droplet size distribution. This generalized threshold function theoretically demonstrates that the relative dispersion, which has been largely neglected to date, essentially controls the cloud-to-rain transition if the li...

The temporal covariance function of irradiance-flux fluctua-tions for Gaussian Schell-model (GSM) beams propagating in atmospheric turbulence is theoretically formulated by making use of the method of effective beam parameters. Based on this formulation, new expressions for the root-mean-square (RMS) bandwidth of the irradiance-flux temporal spectrum due to GSM beams passing through atmospheric...

The construction of the H.E.S.S. (High Energy Stereoscopic System), a superior system of four 12 m imaging atmospheric Čerenkov telescopes, has been completed recently in the Namib desert close to Windhoek, at 1800 m above sea level. This new generation of ground-based gamma-ray detectors has an energy threshold of about 100 GeV in observations at zenith and a sensitivity of about 1% Crab flux ...