CCD Speckle Observations of Binary Stars From the Southern Hemisphere

Two hundred seventy-two magnitude diUerence measures of 135 double star systems are presented. The results are derived from speckle observations using the Bessel V and R passbands and a fast readout CCD camera. Observations were taken at two 60 cm telescopes, namely the Helen Sawyer Hogg Telescope, formerly at Las Campanas, Chile, and the Lowell-Tololo Telescope at the Cerro Tololo InterAmerican Observatory, Chile. The data analysis method is presented and, in comparing the results to those of Hipparcos as well as to recent results using adaptive optics, we —nd very good agreement. Overall, the measurement precision appears to be dependent on seeing and other factors but is generally in the range of 0.10¨0.15 mag for single observations under favorable observing conditions. In four cases, multiple observations in both V and R allowed for the derivation of component V [R colors with uncertainties of 0.11 mag or less. Spectral types are assigned and preliminary eUective temperatures are estimated in these cases.