The FRAM robotic telescope for atmospheric monitoring at the Pierre Auger Observatory

TL;DR

FRAM is a robotic telescope at the Pierre Auger Observatory that uses stellar photometry for passive atmospheric monitoring, complementing laser-based systems, with detailed technical implementation.

Contribution

This paper presents the design, implementation, and operation modes of FRAM, a novel robotic telescope system for atmospheric monitoring at a major cosmic ray observatory.

Findings

FRAM successfully performs atmospheric monitoring without interfering with fluorescence observations.

The system integrates hardware and software for autonomous operation.

Stellar photometry effectively characterizes atmospheric conditions for observatory needs.

Abstract

FRAM (F/Photometric Robotic Atmospheric Monitor) is a robotic telescope operated at the Pierre Auger Observatory in Argentina for the purposes of atmospheric monitoring using stellar photometry. As a passive system which does not produce any light that could interfere with the observations of the fluorescence telescopes of the observatory, it complements the active monitoring systems that use lasers. We discuss the applications of stellar photometry for atmospheric monitoring at optical observatories in general and the particular modes of operation employed by the Auger FRAM. We describe in detail the technical aspects of FRAM, the hardware and software requirements for a successful operation of a robotic telescope for such a purpose and their implementation within the FRAM system.