ISAAC NEWTON GROUP OF TELESCOPES
Roque de los Muchachos Observatory
La Palma, Canary Islands, Spain


Ref.: ING Press Release 4/2007
Date: Friday, 30 november 2007
For immediate release
Also available at http://www.ing.iac.es/PR/press/ing42007.html


FIRST GROUND-LAYER ADAPTIVE-OPTICS SYSTEM FOR GENERAL ASTRONOMICAL OBSERVATIONS


The first ground-layer adaptive optics system in the world that will be used for general 
astronomical observations has been commissioned at the William Herschel Telescope on the 
island of La Palma. The system, which was developed by the Isaac Newton Group of Telescopes, 
in collaboration with scientists from Durham University (UK), the University of Leiden 
(Netherlands) and the ASTRON institute (Netherlands), will permit astronomers to study 
celestial objects in much greater detail. 

The ground-layer adaptive optics system, or GLAS as it is called, works with a high-tech pulsed 
laser. The laser beam is projected from a small telescope mounted behind the secondary mirror 
of the William Herschel Telescope, producing an artificial star in the sky at an altitude of 
15 kilometres. The light coming from the artificial star is detected by a sensor that measures 
the atmospheric distortions. This information is used at a rate of several hundred times 
per second to shape a rapidly adjustable deformable mirror to take out the adverse effects 
of atmospheric turbulence. The somewhat low altitude of the artificial star implies that air 
turbulence nearer the ground is preferentially illuminated and corrected, and therefore it 
is usually referred to as ground-layer adaptive optics. 

The importance of such a laser adaptive optics system goes beyond the immediate scientific 
interests at the William Herschel Telescope. Scientists are currently developing future 
extremely large telescopes that will have mirror diameters of thirty or even forty meters. 
These future huge telescopes will have to rely on adaptive optics with lasers, and correction 
of ground-layer turbulence will be of crucial importance.

This project was made possible through a grant from the Division for Physical Sciences of 
the Netherlands Organisation for Scientific Research, with assistance from the OPTICON 
network funded by the European Union.

The William Herschel Telescope is part of the Isaac Newton Group of Telescopes (ING). 
The ING is owned and operated jointly by the Science and Technology Facilities Council 
(STFC) of the United Kingdom, the Nederlandse Organisatie voor Wetenschappelijk Onderzoek 
(NWO) of the Netherlands and the Instituto de Astrofisica de Canarias (IAC) of Spain. 
The telescope is located in the Spanish Observatorio del Roque de los Muchachos on La Palma, 
Canary Islands, Spain. The international observatory is operated by the Instituto de 
Astrofisica de Canarias (IAC).

CONTACTS:

René Rutten
Isaac Newton Group of Telescopes
Roque de los Muchachos Observatory, La Palma, Spain
Tel: +34 922 425 421
Email: rgmr@ing.iac.es

Richard Myers
Department of Physics
Durham University, UK
Tel: +44 191 334 3692
Email: r.m.myers@durham.ac.uk

Javier Mendez Alvarez
Public Relations Officer
Isaac Newton Group of Telescopes
Roque de los Muchachos Observatory, La Palma, Spain
Tel: +34 922 425 464
Email: jma@ing.iac.es

IMAGES:

Some spectacular photos of the laser being launched from the William Herschel Telescope, 
and images obtained with such a system can be downloaded from:

http://www.ing.iac.es/PR/press/ing42007.html
http://www.ast.cam.ac.uk/ING/PR/press/ing42007.html (mirror site)