European
Southern
Observatory

ELT Instruments
MAORY
Multi-conjugate Adaptive Optics RelaY

As a first-generation ELT instrument, MAORY will help compensate for the distortion of light caused by turbulence in the Earth’s atmosphere which makes astronomical images blurry. MAORY will not make observations itself; rather, it will enable other instruments, such as MICADO in the first instance, to take exceptional images.

In a nutshell

As a first-generation ELT instrument, MAORY will help compensate for the distortion of light caused by turbulence in the Earth’s atmosphere which makes astronomical images blurry. MAORY will not make observations itself; rather, it will enable other instruments, such as MICADO in the first instance, to take exceptional images.

Multi-conjugate Adaptive Optics RelaY

As a first-generation ELT instrument, MAORY will help compensate for the distortion of light caused by turbulence in the Earth’s atmosphere which makes astronomical images blurry. MAORY will not make observations itself; rather, it will enable other instruments, such as MICADO in the first instance, to take exceptional images.

Modern ground-based telescopes cannot achieve their full potential without adaptive optics, sophisticated systems that correct for the blurring effects of the Earth’s turbulent atmosphere and allow us to obtain sharp images of astronomical objects near and far. MAORY is one of the key adaptive optics systems on the ELT. During the first years of operation of the telescope, this instrument will work with near-infrared camera MICADO, moreover MAORY is designed to also feed light to a second instrument in the future. For scientists to make very precise measurements of the positions, brightness, and motions of stars, MICADO needs stable and sharp images across a large field of view — the adaptive optics provided by MAORY will help it to achieve this. 

MAORY will use deformable mirrors and other state-of-the-art systems to correct for different layers of turbulence high above the ELT. In particular, it will rely on six laser guide (artificial) stars, projected from around the circumference of the ELT’s primary mirror and arranged in a circle on the sky, that are used as a reference to measure the distortion caused by the Earth’s atmosphere. These lasers will help MAORY obtain a 3D map of atmospheric turbulence.

Science with MAORY

MAORY is a multi-conjugate adaptive optics system: it will not make scientific observations by itself, but will instead enable other instruments to make observations with excellent image quality. 

In combination with MICADO, and making full use of the increased light-gathering power of the ELT, MAORY will help astronomers to observe distant galaxies at approximately redshifts 2-3 in unprecedented detail. This is an important epoch in the history of the Universe as we are looking at the light from galaxies at the time when astronomers believe that most galaxies formed. Additionally, by taking spatially resolved images with ELT, the individual sites of star formation in the galaxies can be measured and their physical characteristics determined. 

MAORY will also enable MICADO to get a closer look at the massive black hole at the centre of the Milky Way than ever before. The black hole affects the orbits of nearby stars; using previous instruments, astronomers have mapped the motions of these stars down to a distance of 25 light days from the black hole, but the MAORY/MICADO duo will get to a distance of just five light-days.

MAORY is a multi-conjugate adaptive optics system: it will not make scientific observations by itself, but will instead enable other instruments to make observations with excellent image quality.

Instrument Design

MAORY will use nine guide stars (three real stars and six artificial laser stars), state-of-the-art wavefront sensors, and up to three deformable mirrors to measure and correct for turbulence at three different heights in the atmosphere.

To measure atmospheric turbulence, MAORY will observe three natural guide stars around the scientific field-of-view of the camera (MICADO) but it will also use the ELT’s laser guide stars to reach the demanding image quality required for MICADO’s ambitious science goals. The distortion of light by atmospheric turbulence will be measured by wavefront sensors using newly developed detectors capable of reading images hundreds of times per second with low noise.

MAORY uses six large mirrors to deliver light from the focal plane of the telescope to the focal plane of MICADO. By tilting one of those mirrors, it is possible to steer the light beam towards MICADO or the second client instrument. The wavefront sensors for the natural guide stars are physically attached to MICADO to maximise the scientific performance. A dichroic beam splitter in the optical path separates the short wavelength (laser) light into the laser guide star module from the infrared light to the science instruments, and the natural guide star wavefront sensor cameras.

Multi-conjugate AO system

Six laser guide stars and three natural guide stars

Up to two deformable mirrors

in addition to ELT M4 to correct atmospheric turbulence

Two ports for instruments

MICADO and a future spectrograph

Single-conjugate AO

as joint development between MAORY and MICADO

Performance requirements

50% Strehl ratio at 2.2 μm in the best conditions
30% Strehl ratio at 2.2 μm in the median conditions

Sky coverage

50% at the South Galactic Pole

Tools and Documents

Simulator

Tool to predict the exposure time needed to study an object with the instrument, for set environmental conditions

Science Case

Description of the scientific motivations for the instrument, as initially submitted by the Instrument Consortium

Instrument Consortium and Contacts

The MAORY project is managed, together with ESO, by an international consortium composed of three research institutes: the Grenoble Institute for Planetary Sciences and Astrophysics (IPAG), France, the National Institute of Astrophysics (INAF), Italy, and the University of Galway, Ireland.

Principal Investigator

Paolo Ciliegi (INAF Osservatorio Astronomico di Bologna, Italy)

Project Scientist

Carmelo Arcidiacono (INAF Osservatorio Astronomico di Padova, Italy)

Project Manager

Ugo Di Giammatteo (INAF Roma, Italy)

ESO Project Manager

Patrick Cailler

ESO Project Scientist

Elena Valenti

ESO Project Engineer

Paola Amico