Ten metres of aperture. Twelve milliarcseconds of resolution.
ORKID turns the world's most productive astronomical observatory into a visible-light diffraction machine — unlocking science that was previously the exclusive domain of space telescopes.
Imagery · ESO / J. C. Muñoz-Mateos
Key Project
ORKID.
Optical-Resolution Keck Imager + Disperser — the dedicated CELESTE-enabled science instrument at the W. M. Keck Observatory.
ORKID is the science instrument that turns the CELESTE space segment into a functioning observatory. Mounted at the AO-corrected Nasmyth focus of the Keck I telescope, it combines three capabilities in a single optical bench: a visible-light coronagraph for high-contrast imaging, a broadband imager for survey science, and an integral-field spectrograph for spectrophotometric work.
The design philosophy of ORKID follows CELESTE itself: proven components assembled in a novel configuration. The coronagraph uses a vector vortex mask with charge 4 and a Lyot stop optimised for the Keck pupil. The imager uses a back-illuminated EMCCD for sub-electron read noise at visible wavelengths. The IFU samples a 2 × 2 arcsecond field at 50 mas spaxels.
The Brief
i.
Science Objectives
Deliver the full CELESTE science programme at Keck I — Cepheid photometry (CANDLE), exoplanet coronagraphy, AGN reverberation, galaxy morphology, and supernova spectroscopy — in a single instrument that operates nightly alongside other Keck programs.
ii.
Observables & Measurements
Visible-band (0.4 – 1.0 μm) coronagraphic images at 10⁻⁸ raw contrast; broadband survey imaging at 12 mas resolution; integral-field spectra at R ≈ 70 over 0.4 – 1.0 μm in a 2 × 2 arcsecond field.
iii.
Key Functional Requirements
Vector vortex coronagraph, charge 4, with IWA = 2 λ/D. EMCCD detector with QE > 90% at 700 nm. IFU with 50 mas spaxels. Thermal control maintaining wavefront stability over 4-hour science blocks.
iv.
CELESTE Uniqueness
ORKID is the only planned instrument that combines visible coronagraphy and integral-field spectroscopy in the same AO-corrected focal station — and the only instrument designed from the ground up to exploit an orbiting laser guide star. No existing Keck instrument delivers diffraction-limited visible-light coronagraphy.