Timescale measurements by previous authors

At a number of astronomical observatories in the late 1970s and early 1980s experiments were undertaken which were designed to investigate the timescales for changes in the image plane speckle patterns seen when observing unresolved point sources through large telescopes. Scaddan & Walker (1978); Dainty et al. (1981); Parry et al. (1979) found that there were two dominant timescales - a slow timescale corresponding to motion of the centroid of the speckle pattern, and a fast timescale corresponding to changes within the speckle pattern. The faster timescale is most relevant to high resolution imaging, and they developed a method for accurately measuring this timescale from the temporal autocorrelation of time-resolved photometric observations at a point in the image plane of the telescope. It will be of interest to compare my results to previous work in the field, so I will give a brief description of their method here.