The CASTLE telescope, first curved sensors on-sky demonstration for astronomy

CASTLE, the Calar Alto Schmidt-Lemaître Explorer is the very first on-sky demonstration of curved sensors for an astronomical application. It will address two cutting-edge astrophysical topics: the search for the electromagnetic counterpart of gravitational waves and the observation of Low surface brightness objects. The first light is planned for Summer 2022, it is installed at the summit of the Calar Alto Observatory in Andalousia, south of Spain.
The project is done in collaboration with the companies Pyxalis in Grenoble, Winlight in the south of France and Sinoptic in Shanghai.
The scientific Consortium gathers the Observatory of Strasbourg, the Institute of Astronomy of Andalousia and the Laboratoire d’Astrophysique de Marseille.
This is a 1.2M€ project, funded by the MERAC foundation and the European Astronomical Society-EAS, the French research agency-ANR, the European Community-EC through the European Research Council-ERC and the French national research center-CNRS.

Project Lead and scientist: Simona LOMBARDO (
Opto-mechanical architect: Eduard MUSLIMOV
Mechanical engineer: Ali FAHAD
PhD Student, integration & tests: Kelly JOAQUINA
French side: Emmanuel HUGOT (CNRS-LAM) & Pierre Alain DUC (CNRS-ObAS)
Spanish side: Francisco PRADA (CSIC-IAA)

Related publications
White paper:  Lombardo, Hugot, Duc, Prada et al “CASTLE: performances and science cases”
Simona Lombardo+2019 “Next-generation telescopes with curved focal surface for ultra-low surface brightness surveys”, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P – Oxford Open Option A, In press, ⟨10.1093/mnras/stz2068⟩. ⟨hal-02263343⟩
Eduard Muslimov+2017, “Fast, wide‐field and distortion‐free telescope with curved detectors for surveys at ultralow surface brightness”. Applied optics, Optical Society of America, 2017, 56 (31), pp.8639-8647. ⟨10.1364/AO.56.008639⟩. ⟨hal-01678500⟩


Picture credit E. Muslimov – CNRS-LAM

(The project is co-funded by the CNRS, the CSIC, the MERAC Foundation and the European Commission through the ERC-STG-2015 – ICARUS-678777 and the ERC-PoC-CURVE-X-839271)