Why adaptive optics?
In a major technological break-through in ground-based astronomy, a new device, known as the VLT Adaptive Optics Prototype (see eso8717, eso8808, and eso8707), has now proved its ability to overcome this natural barrier during a series of successful tests in the period 12 – 23 October 1989. They were performed at the coudé focus of the 1.52 m telescope at the Observatoire de Haute Provence (OHP), France (see photo). The extensive tests showed that it was possible effectively to “neutralize” the atmospherically induced smearing of a stellar image by continuously monitoring the motion of the sharp sub-images and then focussing them into one spot by means of a deformable mirror. In this way stellar images were obtained at infrared wavelengths whose sharpness was only limited by the telescope aperture (this is referred to as diffraction limited imaging). On each of ten nights, exposures were made of about 10 bright stars through 4 or 5 infrared filters. Several integrations were made thro
