A telescope control and scheduling system for the Gravitational-wave Optical Transient Observer

TL;DR

This paper presents the development and implementation of G-TeCS, a control system for the GOTO telescope, enabling autonomous sky surveys and follow-up observations of gravitational-wave events, advancing multi-messenger astrophysics.

Contribution

It introduces G-TeCS, a novel software system for controlling multiple telescopes autonomously for gravitational-wave counterpart searches.

Findings

GOTO prototype achieved first light in June 2017.

G-TeCS successfully automated survey and follow-up procedures.

Simulations predict scalable global telescope network capabilities.

Abstract

The detection of the first electromagnetic counterpart to a gravitational-wave signal in August 2017 marked the start of a new era of multi-messenger astrophysics. An unprecedented number of telescopes around the world were involved in hunting for the source of the signal, and although more gravitational-wave signals have been since detected, no further electromagnetic counterparts have been found. In this thesis, I present my work to help build a telescope dedicated to the hunt for these elusive sources: the Gravitational-wave Optical Transient Observer (GOTO). I detail the creation of the GOTO Telescope Control System, G-TeCS, which includes the software required to control multiple wide-field telescopes on a single robotic mount. G-TeCS also includes software that enables the telescope to complete a sky survey and transient alert follow-up observations completely autonomously, whilst monitoring the weather conditions and automatically fixing any hardware issues that arise. I go on to describe the routines used to determine target priorities, as well as how the all-sky survey grid is defined, how gravitational-wave and other transient alerts are received and processed, and how the optimum follow-up strategies for these events were determined. The GOTO prototype, situated on La Palma, saw first light in June 2017. I detail the work I carried out on the site to help commission the prototype, and how the control software was developed during the commissioning phase. I also analyse the GOTO CCD cameras and optics, building a complete theoretical model of the system to confirm the performance of the prototype. Finally, I describe the results of simulations I carried out predicting the future of the GOTO project, with multiple robotic telescopes on La Palma and in Australia, and how G-TeCS might be modified to operate these telescopes as a single, global observatory.