THE FIRST DIFFRACTION-LIMITED IMAGES FROM THE W-M-KECK-TELESCOPE

The first diffraction limited, 0:'' 05 resolution, images on the W. M. Keck Telescope have been obtained at a wavelength of 2.2 mu m. These images were part of an experiment to test the suitability of the Keck Telescope for speckle imaging. In order to conduct this test, it was n ecessary to modify the pixel scale of the Keck facility Near Infrared Camera (NIRC) to optimally sample the spatial frequencies made availab le by the Keck telescope. The design and implementation of the externa l reimaging optics, which convert the standard f/25 beam from the seco ndary min-or to f/182, are described here. Techniques for reducing spe ckle data with field rotation on an alt-az telescope are also describe d. Three binary stars were observed in this experiment with separation s as small as 0:'' 05. With only 100 frames of data on each, a dynamic range of at least 3.5 mag was achieved in all cases. These observatio ns imply that a companion as faint as 14.5 mag at 2.2 mu m could be de tected around an 11th magnitude point source.