All-sky Guide Star Catalog for CSST

TL;DR

This paper presents the construction of a guide star catalog for the CSST's Fine Guidance Sensor, utilizing Gaia DR3 data and advanced algorithms to ensure uniform sky coverage and meet guidance accuracy requirements.

Contribution

We developed a guide star catalog for CSST's FGS using Gaia DR3 data, applying the Voronoi algorithm for uniform star distribution and validating its performance through simulations.

Findings

Catalog provides adequate sky coverage and guidance accuracy.

The approach ensures uniform star distribution for optimal FGS performance.

Performance meets the operational requirements of the CSST FGS.

Abstract

The China Space Station Telescope (CSST) is a two-meter space telescope with multiple back-end instruments. The Fine Guidance Sensor (FGS) is an essential subsystem of the CSST Precision Image Stability System to ensure the required absolute pointing accuracy and line-of-sight stabilization. In this study, we construct the Main Guide Star Catalog for FGS. To accomplish this, we utilize the information about the FGS and object information from the Gaia Data Release 3. We provide an FGS instrument magnitude and exclude variables, binaries, and high proper motion stars from the catalog to ensure uniform FGS guidance capabilities. Subsequently, we generate a HEALPix index, which provides a hierarchical tessellation of the celestial sphere, and employ the Voronoi algorithm to achieve a homogeneous distribution of stars across the catalog. This distribution ensures adequate coverage and sampling of the sky. The performance of the CSST guide star catalog was assessed by simulating the field of view of the FGS according to the CSST mock survey strategy catalog. The analysis of the results indicates that this catalog provides adequate coverage and accuracy. The catalog's performance meets the FGS requirements, ensuring the functioning of the FGS and its guidance capabilities.