A New Method for Aerosol Measurement using Wide-field Photometry

Abstract

We present a new method to measure the vertical aerosol optical depth (VAOD) during clear nights using a wide-field imager - a CCD camera with a photographic lens on an equatorial mount. A series of 30-second exposures taken at different altitudes above the horizon can be used to measure the VAOD with a precision better than 0.008 optical depths within a few minutes. Such a measurement does not produce any light and is thus suitable for use at sites where other astronomical instruments are located. The precision of the VAOD measurement depends on laboratory calibration of spectral properties of the system and of the response of the camera electronics to varying illumination levels, as well as careful considerations of details of stellar photometry and modelling of the dependence of measured stellar fluxes star color and position within the field of view. The results obtained with robotic setups at the future sites of the Cherenkov Telescope Array show good internal consistency and agreement with the simultaneous measurements from a Sun/Moon Photometer located at the same site.

arXiv commentAccepted in Astronomical Journal

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Cited by in corpus (9)

• Correcting Imaging Atmospheric Cherenkov Telescope data with atmospheric profiles obtained with an elastic light detecting and ranging system
• The FRAM robotic telescope for atmospheric monitoring at the Pierre Auger Observatory
• A novel image correction method for cloud-affected observations with Imaging Atmospheric Cherenkov Telescopes
• Characterisation of the Atmosphere in Very High Energy Gamma-Astronomy for Imaging Atmospheric Cherenkov Telescopes
• A 1.8 m class pathfinder Raman LIDAR for the Northern Site of the Cherenkov Telescope Array Observatory -- Technical Design
• A 1.8 m class pathfinder Raman LIDAR for the Northern Site of the Cherenkov Telescope Array Observatory -- Performance
• FRAM Next Generation at the Pierre Auger Observatory: cloud monitoring in the age of CMOS cameras
• Prospects for the detection of gamma rays using Cherenkov telescopes enhanced by a ground array observatory
• Aerosol Measurement in B, V, and R Filters using Wide-field Photometry