Atmospheric sensing for the H.E.S.S. array


Several atmospheric monitoring instruments have been installed at the H.E.S.S. gamma-ray observatory in Namibia. Firstly, Heitronics KT19 infrared radiometers, aligned paraxially with the H.E.S.S. telescopes, measure the infrared radiation of the water molecules. These allow us to detect clouds crossing the telescopes' field of view and to estimate the humidity present in the atmosphere. For a general estimate of the atmosphere’s transmittance, i.e. the detection of any light-attenuating aerosols, a ceilometer, which is a LIDAR with built-in atmospheric data reduction code, is being used. It will be complemented soon by an instrument which will measure the transmissivity of the atmosphere at different wavelengths up to 500m above the ground. The overall status of the weather is monitored by a fully automated weatherstation. This paper describes the setup, the data analysis and how this will be used in order to improve the knowledge of the telescopes' effective collection area.

Michael Aye
Michael Aye
Research Scientist in Planetary Science

My research interests include remote sensing of surfaces, related machine learning studies and open source software.