OPTICAL-PATH STABILITY AND FRINGE TRACKING IN OPTICAL STELLAR INTERFEROMETRY

We analyze the problems of fringe pattern estimation in optical stella r interferometry that are associated with optical path errors. Our fir st finding is that an optimal fringe tracking system must track with p ath length errors of less than about one-eighth of the coherence lengt h. The second is that if phase closure estimation is to be achieved at the lowest possible light levels, the time scale of fringe wander mus t not be less than about 10% of the total observation time. (C) 1998 P ublished by Elsevier Science B.V. All rights reserved.