The PLACID active coronagraphic imager instrument: commissioning status

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.

21 pages, 17 figures, SPIE Astronomical Telescopes + Instrumentation 2026, Paper 14149-20