New Adaptive Optics Module for Interferometry

Auxiliary Telescopes and Satellites

Starlight Shines Brightly Above ParanalNAOMI, or the New Adaptive Optics Module for Interferometry, is about to put the Very Large Telescope Interferometer (VLTI) on steroids. NAOMI modules will be installed on each of ESO’s 1.8-metre Auxiliary Telescopes (ATs), which form part of the VLTI at Paranal Observatory, bringing adaptive optics technology to the ATs.

Why? The ATs were equipped originally with a visible-light sensor called STRAP or System for Tip/tilt Removal with Avalanche Photodiodes. The STRAP system used a fast-steering mirror to correct the slight, but rapid, motion of the image of a star caused by the turbulence of the Earth's atmosphere. Under good seeing conditions, STRAP provided corrections that allowed astronomers to observe with the VLTI. But the system has limitations — as soon as the conditions in the atmosphere degrade below a seeing of 1 arcsecond, the quality of the observations decays instantly. With NAOMI, the observations will be able to continue even when the conditions are less than superb, and they will be better under all conditions.

Paranal NightsThe goal of the project is to equip all four ATs with NAOMI modules, which contain a basic adaptive optics (AO) system, in place of the current STRAP sensor. As the ATs are small telescopes, they don’t require an advanced AO system such as SPHERE; NAOMI’s simpler implementation is sufficient to get the job done. With NAOMI, the ATs will be less sensitive to atmospheric conditions. The sensitivity of the VLTI’s current instruments like AMBER and PIONIER will be improved and second-generation instruments like GRAVITY and MATISSE will be able to reach their full potential.

The four NAOMI modules will arrive on Paranal in the first half of 2018.


This table lists the global capabilities of the system. The authoritative technical specifications as offered for astronomical observations are available from the Science Operation page.

Site: Paranal Observatory
Telescope: ESO 1.8-metre Auxiliary Telescopes (ATs)
Focus: Coudé
Type: Adaptive optics interface to the VLTI
Wavelength coverage: Near-infrared
Spatial resolution:
Spectral resolution:
First light date: 2018
Images taken with the instrument:
Images of the instrument: Link
Press Releases with the instrument: Link
Science goals: Adaptive optics system to improve VLTI


ESO in-house project together with IPAG