Group Delay Tracking With The

Abstract:  obability of tracking error, rather than on signalto -noise performance. Experimental results from both laboratory studies and stellar observations are presented. These show the first closed-loop operation of a fringe tracking system based on observations of group delay with a stellar interferometer. A new photon counting PAPA detector is also described, which was developed for use in this work. The design principles of the PAPA camera are outlined, and the potential sources of image artifacts are identified. These artifacts arise from the use of optical encoding with Gray coded masks. The new camera is distinguished by its mask-plate, which was designed to overcome artifacts due to vignetting. New lens mounts are also presented which permit a simplified optical alignment without the need for tilt-plates. The performance of the camera is described and its images are shown to be free of the e#ects of vignetting. Declaration of Originality To the best of my knowledge, this thesis cont