Technique for pointing model parameters estimation for imaging atmospheric Cherenkov telescopes

Dmitriy P. Zhurov, Oleg A. Gress, Denis N. Sidorov

Irkutsk National Research Technical University, Applied Physics Institute of Irkutsk State University, Melentiev Energy Systems Institute SB RAS

The article discusses a technique to estimate parameters of a pointing model for atmospheric Cherenkov telescopes (IACT) by deviations of image positions of stars on the focal plane during calibration measurements. The model for calculation of the telescope position and estimation of the focal plane rotation angle using shaft encoders readouts are presented. To estimate the parameters, it is proposed to use gradient optimization methods with an initial approximation obtained from linear regression under the assumption of a small focal plane rotation angle, followed by a posterior probability distributions calculation using Markov chain Monte Carlo method to precise the parameters. Results of technique tests on simulated data are presented, the approach allows to obtain robust estimates of the parameters.

imaging atmospheric Cherenkov telescopes, IACT, pointing model, parameters estimation