The Innsbruck/ESO sky models and telluric correction tools^*

The possibility of atmospheric monitoring for Čerenkov telescopes

¹ Instituto de Astronomía, Universidad Católica del Norte, Avenida Angamos 0610, Antofagasta, Chile
² Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstrasse 25/8, 6020 Innsbruck, Austria
³ Department of Astrophysics, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria

^a e-mail: Stefan.Kimeswenger@gmail.com; presenting author

Published online: 26 March 2015

Abstract

Ground-based astronomical observations are influenced by scattering and absorption by molecules and aerosols in the Earth's atmosphere. They are additionally affected by background emission from scattered moonlight, zodiacal light, scattered starlight, the atmosphere, and the telescope. These influences vary with environmental parameters like temperature, humidity, and chemical composition. Nowadays, this is corrected during data processing, mainly using semi-empirical methods and calibration by known sources. Part of the Austrian ESO in-kind contribution was a new model of the sky background, which is more complete and comprehensive than previous models.

While the ground based astronomical observatories just have to correct for the line-of-sight integral of these effects, the Čerenkov telescopes use the atmosphere as the primary detector. The measured radiation originates at lower altitudes and does not pass through the entire atmosphere. Thus, a decent knowledge of the profile of the atmosphere at any time is required. The latter cannot be achieved by photometric measurements of stellar sources. We show here the capabilities of our sky background model and data reduction tools for ground-based optical/infrared telescopes. Furthermore, we discuss the feasibility of monitoring the atmosphere above any observing site, and thus, the possible application of the method for Čerenkov telescopes.