We present first on-sky performance results of KalAO, the natural guide star adaptive optics imager on the 1.2m Swiss telescope in La Silla, Chile. It is designed to reach at least 30% Strehl in order to detect stellar companions as close as the 150mas in visible-light, at diffraction limit. KalAO was built to search for binarity in planet hosting stars by following-up planet candidates primarily from the TESS satellite survey. The optical design is optimised for the 450 to 900nm wavelength range and is fitted with SDSS griz filters. Wavefront control works down to I-magnitude 10 stars in order to probe the same parameter space as radial velocity instruments such as HARPS and NIRPS. The system first closed the loop on sky in November 2023 and reached diffraction limit imaging in February 2024. It can carry out AO corrected observation of up to 500 targets in one night, with a Strehl ratio of ≈30%.
The Spectrograph of the RISTRETTO instrument is now currently being manufactured. RISTRETTO is an instrument designed to detect and characterize the reflected light of nearby exoplanets. It combines high contrast imaging and high resolution spectroscopy to detect the light of exoplanets. The high resolution spectrograph subject of this paper uses the doppler effect to disentangle the planetary signal from the stellar light leaks. In this paper we describe the final design of the spectrograph and report the status of its construction. The RISTRETTO spectrograph has seven diffraction limited spaxels. The spectrograph’s resolution is 130000 in the 620-840 nm band. It is designed in a similar way as HARPS and ESPRESSO, being a warm, thermally controlled spectrograph under vacuum. It is designed to be compact and self contained so that it could be installed on different telescopes. It is however tailored to be installed on a nasmyth platform of a VLT telescope. We present updates to the design and the manufacturing of the instrument. In particular we present the performance of the thermal enclosure.
The RISTRETTO project is aiming to build an instrument that will detect the reflected light from close-by exoplanet. It is a two stage instrument: An extreme AO system in the visible, followed by a seven spaxel single mode High resolution Spectrograph. In this paper we present the design of this spectrograph: a classical echelle spectrograph fed with single mode fibers. Standard single mode fibers have been chosen and are forming a long tilted slit in order to have the right order spacing on the detector. The instrument will be under vacuum and thermally controlled in order to make it stable.
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