We present 119 position angle and separation measures of 86 double stars observed by way of speckle interferometry with the University of Toronto Southern Observatory 60 cm telescope at Las Campanas, Chile. Speckle interferograms are recorded with a bare (unintensified) front-illuminated CCD in a fast subarray-readout mode. Position angles and separations are determined by a weighted least-squares fitting algorithm applied to the binary power spectra, and the 180-degree ambiguity in the position angle inherent in this approach is resolved by bispectral analysis. In this configuration the 60 cm telescope exhibits near-diffraction-limited performance. Initial results indicate that our separation measures have a root-mean-square (rms) deviation of 6.6 +/- 1.0 milliarcsecond (mas) and our position angles have an rms deviation of 1.73 +/- 0.26 degrees when judged against the ephemeris positions of a small sample of binaries with previously well-determined orbits (Refer to PDF file for exact formulas).

Publication Date



© 1997 American Astronomical Society

We would like to thank the University of Toronto Southern Observatory for observing time, Robert Garrison and Brian Beattie of the University of Toronto for logistics help in preparation for the run, and Freddy Orrego Goya and Steve Steele at Las Campanas for their assistance. We also thank William Hartkopf of CHARA for providing an up-to-date orbit for Bu 101 and Geoffrey Douglass of the USNO for providing observational data from the WDS used in Fig. 6.

This work was supported by a grant from NASA administered by the American Astronomical Society yand by funding for detector development from the NSF S/IUCRC Program and the New York State CAT Program.ISSN:1538-3881

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


RIT – Main Campus