THE ULTRA-HIGH-RESOLUTION FACILITY AT THE ANGLO-AUSTRALIAN TELESCOPE

The Ultra-High-Resolution Facility (UHRF) has been commissioned at the coude focus of the Angle-Australian Telescope (AAT), and provides a resolving power of R approximate to 10(6). This is the highest spectral resolution ever obtained by an optical astronomical spectrograph, and is intended mainly for astrophysical studies of cool interstellar clouds. This paper describes the development of this ambitious project, which includes diffraction-limited optical components, very tight specification for the optical. configuration, and a new type of image slicer which allows ultra-high-resolution work towards faint stars. Astrophysical results from the first observing runs are presented to demonstrate the performance in terms of both resolution and throughput.