Introduction

Continued progress in observational astronomy requires access to increasingly large and sophisticated telescopes and instrumentation. It is widely recognized that the next generation ground-based optical/infrared telescope will need an effective aperture in the range 30-50 meters and near diffraction-limited resolution. A conventional telescope of such a size, if it could be built, could cost a billion dollars or more. However, if some functionality, such as the ability to point at targets anywhere in the sky, is sacrificed, the cost can be reduced significantly. The LAMA telescope will use advanced technologies (liquid-mirror, adaptive optics and interferometry) to achieve large aperture and high resolution at a small fraction of the cost.

Concept

The LAMA  telescope employs an array of fixed 10-meter liquid-mirror telescopes. These are located in a closely-packed configuration with an overall diameter of 54 meters. Approximately 62% of the light that falls within this area is collected and focussed on a common detector. This gives the array a light-collecting power equivalent to that of a 42-metre telescope.

Tracking secondary mirrors and active optics allows the array to follow objects for several minutes as they pass overhead. At any given time, the array can point anywhere within a 4-degree diameter circle centered on the zenith. This makes 2400 square degrees, about 6% of the entire sky, accessible to the telescope.

Light from all the telescopes is brought to a common focus in a central beam-combining room. Here the light beams interfere constructively to produce an image with a resolution of several milliarcsec. Moving mirrors, controlled by a phase-tracking system, equalize the optical path lengths from all elements of the array to within a fraction of a micron.

Equipped with optical and infrared detectors, the array will provide images which, over the course of a year, will reach detection limits measured in picoJanskys.