Calibration of the ASTRI-1 Cherenkov camera

The ASTRI project, led by the Italian National Institute for Astrophysics (INAF), aims to deploy an array of nine small-sized (4-m diameter) Imaging Atmospheric Cherenkov Telescopes at the Teide Observatory in Tenerife. The system will study astronomical sources emitting in the very high-energy range above 1 TeV up to 200 TeV. Each telescope is equipped with a Cherenkov camera based upon Silicon Photo-Multiplier (SiPM) sensors. The focal plane is composed of 2368 pixels arranged in 37 Photon Detection Modules (PDMs) of 8×8 pixels covering a field of view of about 10.5 degree. The camera electronics is based on a peak detection circuit and is designed to perform self-trigger of the whole focal plane in order to detect and digitize Cherenkov signals while minimizing the data transfer volume. One of the nine telescopes (ASTRI-1) is already in its commissioning phase, collecting data since September 2024 when the first industrial version of the ASTRI Cherenkov camera was mounted on the telescope. In this contribution we report on the camera calibration carried out at the beginning of the commissioning phase and on the system stability monitoring through on-site daily calibration runs. All the calibrations have been performed with the camera internal calibration system that allows the on-site extraction of the optimal camera configuration parameters and of the calibration coefficients needed for the data analysis.