NAOMI, the Nasmyth Adaptive Optics for Multi-purpose Instrumentation, is an adaptive optics system for the William Herschel Telescope (link opens in a new window) of the Isaac Newton Group of telescopes (ING) in La Palma. NAOMI was designed and built in collaboration with the University of Durham and the ING.
Until recently, the quality of astronomical images delivered by ground-based telescopes with apertures larger than about 20 centimetres has been limited by the blurring effects of the Earth's atmosphere. However, over the past decade, several research groups have demonstrated that applying adaptive optics (AO) can compensate for these atmospheric distortions in real time and deliver images that are close to the limits imposed by diffraction.
In an AO system, the deformations of the incoming light wave due to atmospheric turbulence are measured and corrected in real time, typically hundreds of times per second, by analysing the light from a bright star in the field, and changing the shape of a flexible mirror in the light path to cancel the deformations.
On the best astronomical sites the resolution of images taken at ground level is typically about 0.5 arc seconds, while the limiting resolution of a 4 metre telescope like the WHT without the atmosphere would be about 10 times better than this. During commissioning of NAOMI in September 2000, images with 0.1 arc second resolution were taken at near-infrared wavelengths.
NAOMI is optimised for near-infrared science from 1 to 2.5 micrometres. It is also suitable for correcting optical images.