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arXiv · 2608.28226

The PLACID active coronagraphic imager instrument: commissioning status

Ruben Tandon·Lucas Marquis·Liurong Lin·Derya Öztürk Çetni·Axel Potier·Audrey Baur·Iljadin Manurung·Matthias Brändli·Martin Rieder·Daniele Piazza·Laurent Jolissaint·Jonas G. Kühn
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Abstract

The world's first adaptive stellar coronagraph, the Programmable Liquid-crystal Active Coronagraphic Imager for the 4-m DAG telescope (PLACID) uses a spatial light modulator operating from H- to Ks-band to dynamically adjust the focal-plane phase mask entirely in software. Positioned between the TROIA XAO system and the DIRAC infrared detector, PLACID was installed on the Nasmyth platform of the Turkish 4-m DAG telescope in 2025, followed by optical alignment and successful preliminary acceptance tests with the calibration light source in early 2026. On-sky commissioning is expected, as soon as the TROIA XAO system will be operational. When on-sky, it will enable high-contrast imaging of exoplanets, brown dwarfs, disks, and binary systems, being able to easily deploy any desired phase pattern in the focal plane. Upcoming features include self-calibration of non-common path aberrations, coronagraphic nulling of binary-stars, and coherent differential imaging. We present the preliminary acceptance procedures and internal alignment results, discovery-space estimates, new binary star features and observation tools, to be ready for first science by late 2026/early 2027.

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Ruben Tandon, Lucas Marquis, Liurong Lin, Derya Öztürk Çetni, Axel Potier, Audrey Baur, Iljadin Manurung, Matthias Brändli, Martin Rieder, Daniele Piazza, Laurent Jolissaint, Jonas G. Kühn. 2026-08-28. The PLACID active coronagraphic imager instrument: commissioning status. https://doi.org/10.1117/12.3102879

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