Challenges in focal plane and telescope calibration for High-Precision Space Astrometry

TL;DR

This paper discusses the challenges and proposed solutions for calibrating the focal plane and optical distortion in high-precision space astrometry missions like heia, aiming for sub-microarcsecond accuracy to study exoplanets.

Contribution

It introduces a framework for calibrating large-format detectors and optical distortion using field stars, with laboratory validation and potential applications for future observatories.

Findings

Feasibility of calibrating large-format detectors in laboratory settings.

Use of field stars as metrological sources for optical distortion calibration.

Laboratory confirmation of simulation-based performance predictions.

Abstract

With sub-microarcsecond angular accuracy, the \theia telescope will be capable of revealing the architectures of nearby exoplanetary systems down to the mass of Earth. This research addresses the challenges inherent in space astrometry missions, focusing on focal plane calibration and telescope optical distortion. We propose to assess the future feasibility of large-format detectors (50 to 200 megapixels) in a controlled laboratory environment. The aim is to improve the architecture of the focal plane while ensuring that specifications are met. The use of field stars as metrological sources for calibrating the optical distortion of the field may help to constrain telescope stability. The paper concludes with an attempt to confirm in the laboratory the performance predicted by simulations. We will also address the possibility of using such techniques with a dedicated instrument for the Habitable World Observatory.