Histograms of the standard deviations of RA and Dec coordinates of stars, after imaging a single plate several times, fitting astrometry to each image, and deriving standard deviations of the coordinates for each star. The data sample includes stars that have been imaged from four to 52 times. The histogram plotted with a thin line is for the single-exposure plate #886, the histogram plotted with a thick line is for the triple-exposure plate #882.