The ELT-GSC1.0 is the first public release of the all-sky reference catalogue that will support guiding and adaptive-optics (AO) operations of ESO's Extremely Large Telescope (ELT) and its first-generation instruments, including MICADO and the MORFEO multi-conjugate AO module. It is built directly on the JWST Guide Star Catalogue version 3.1 (GSC3.1), kindly made fully available to ESO by the Space Telescope Science Institute (STScI).
First Public Release of the ELT Guide Star Catalogue Version 1.0 (ELT-GSC1.0)
Published: 01 Jul 2026
GSC3.1 became the operational catalogue for the JWST Guide Star Selection Subsystem in December 2024 and represents the current state of the art in all-sky guide-star catalogues, combining Gaia DR3 astrometry and photometry with measurements from several surveys including 2MASS, Pan-STARRS, SDSS, SkyMapper, the NOIRLab Source Catalog, and the VVV/VIRAC and Galactic Nucleus surveys. With respect to GSC3.1, ELT-GSC1.0 is limited to objects with Dec < 30 deg and adds a small set of derived columns that are needed for ELT operations and have no equivalent in the source catalogue: synthetic 2MASS J, H and Ks magnitudes for sources with optical photometry but no measured near-infrared magnitudes; a flag identifying sources with sufficient photometric coverage to be treated as bona-fide stars, an operational effective temperature derived from broad-band colours, and two suitability flags marking objects that can be used as guide stars (GS) for telescope guiding and as natural guide stars (NGS) for AO wavefront sensing.
The catalogue is available for queries and dowload via the catalog query interface or TAP. Individual catalogue tiles are also included into ASP or can be retrieved programmatically.
More information are available in the accompanying documentation. The colection DOI is doi.org/10.18727/archive/112