AO Instruments


Systems in operation at the VLT


The prime objective of the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument for the VLT is the discovery and study of new extra-solar giant planets orbiting nearby stars by direct imaging of their circumstellar environment. SPHERE will be located at the Nasmyth focus of the VLT. The instrument as shown in the figure above is composed of 4 major subsystem: the common path including the powerfull AO system and the three science instruments IRDIS, IFS and ZIMPOL each fed by a sophisticated pupil apodized Lyot, Lyot, or phase mask coronagraph. More information is available on a separate page.


NaCo sets out for NAOS-CONICA. It provides adaptive optics assisted imaging, imaging polarimetry, coronography and spectroscopy, in the 1-5 microns range. More information is available on a separate page.


The VLT cryogenic high-resolution infrared echelle spectrograph CRIRES is located at the Nasmyth focus A of UT1 (Antu). It provides a resolving power of up to 105 in the spectral range from 1 to 5 µm when used with a 0."2 arcsec slit. CRIRES can boost all scientific applications aiming at fainter objects, higher spatial (extended sources), spectral and temporal resolution. Simultaneous spectral coverage is maximized through a mosaic of four Aladdin III InSb arrays providing an effective 4096 x 512 focal plane detector array in the focal plane. Adaptive Optics (MACAO - Multi-Applications Curvature Adaptive optics) is used to optimize the signal-to-noise ratio and the spatial resolution. More information is available on a separate page.


SINFONI is a near-infrared (1.1 - 2.45 µm) integral field spectrograph fed by an adaptive optics module, currently installed at the Cassegrain focus of UT4. The spectrograph operates with 4 gratings (J, H, K, H+K) providing a spectral resolution around 2000, 3000, 4000 in J, H, K, respectively, and 1500 in H+K - each wavelength band fitting fully on the 2048 pixels of the Hawaii 2RG (2kx2k) detector in the dispersion direction. The spatial resolution is selectable from 0.25", 0.1" to 0.025" per image slice, which corresponds to a field-of-view of 8"x8", 3"x3", or 0.8"x0.8" respectively. The instrument can be also used for seeing limited open loop observations. More information is available on a separate page.


MACAO, which stands for Multi-Application Curvature Adaptive Optics, is an ESO in-house developed 60 elements curvature adaptive optics system. MACAO-VLTI is the application of this AO principle to be used by the VLT interferometer (VLTI). Four MACAO-VLTI systems have been installed at the each UT Coude' focii feeding the VLTI delay lines with a corrected IR beam from 1000-13000nm with up to 50% Strehl @ 2.2microns.


The Adaptive Optics Facility (AOF) is an upgrade of a 8m Unit telescope of the Paranal Observatory with an Adaptive Secondary Mirror (DSM) to make this telescope an Adaptive Telescope providing turbulence corrected images at all focii, without the addition of adaptive modules and supplementary optics in front of the instruments. The AOF is working at the VLT since end 2016 with two adaptive modules (GRAAL and GALACSI) as well as 4 Laser guide stars. The AOF booklet gives an overview of the AOF.

Systems studies for the E-ELT

The Adaptive Telescope

In the frame of the E-ELT project the Adaptive Optics group is following the manufacturing of one sub unit of the telescope: the M4 adaptive mirror


AO instruments in design phase

Two adaptive optics modules (LTAO for HARMONI, MAORY) are currently in design phase. More information is available on a separate page.

Systems studies for the VLT

A phase A is starting to study a new instrument for UT4 making use of the AOF.

Demonstrators of new Adaptive Optics instruments


The Multi-Conjugate Adaptive Optics Demonstrator (MAD) is a prototype MCAO system which aims to demonstrate in the laboratory and on sky the feasibility of different MCAO reconstruction techniques in the framework of the E-ELT concept and the 2nd Generation VLT Instruments. After an extended period of laboratory testing MAD was installed at the VLT Nasmyth focus for performing some validation runs and science demosntration runs. The system was finally dismounted and sent back to ESO-Garching for further tests in laboratory.

The MAD project is led and developed by ESO with the collaboration of INAF-OsservatorioAstrofisico di Arcetri (INAF-OAA), the INAF-Osservatorio Astronomicodi Padova (INAF-OAPD) and the Faculdade de Ciências de Universidade de Lisboa (FCUL).

More information is available on a separate page.


The high Order Test Bench was developped in the frame of the European Programmme FP6 Opticon JRA1 to implement extreme adaptive optics on a test bench with realistic telescope conditions reproduced by star and turbulence generator. The objective was to compare two different wavefront sensors including their behavior to different errors during calibration and other noises. The complete list of objective as well as the test are presented on a separate page.