Speckle observations of binary stars with the WIYN telescope. IV. Differential photometry

Five hundred seventy-six magnitude difference measures are presented for 260 binary stars. These measures are derived from CCD-based speckle observations taken at the WIYN 3.5 m telescope at Kitt Peak National Observatory during the period 1997 - 2000. Separations of the systems range from over 1 down to near the diffraction limit of the telescope. A study of multiple measures of the same targets indicates that the measures have a typical uncertainty of better than 0.13 mag per 2 minute observation, and that multiple observations can be averaged to arrive at smaller uncertainties. Results presented here are also compared, insofar as it is possible, with measures in the Hipparcos Catalogue and to previous studies using adaptive optics. No major systematic errors were identified.