Two hundred seventy-seven position angle and separation measures of 154 double stars are presented. Three of the systems were previously unknown to be double, and 16 other systems were discovered earlier this decade by the Hipparcos satellite. Measures are derived from speckle observations taken with the Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5 m telescope located at Kitt Peak, Arizona. Speckle images were obtained using two different imaging detectors, namely, a multianode microchannel array (MAMA) detector and a fast-readout CCD. A measurement precision study was performed on a sample of binaries with extremely well known orbits by comparing the measures obtained here to the ephemeris predictions. For the CCD, the root mean square (rms) deviation of residuals was found to be 3.5 milliarcseconds (mas) in separation and 1.2d in position angle, while the residuals of the MAMA data varied depending on the magnification used and seeing conditions but can be comparable or superior to the CCD values. In addition, the two cameras were compared in terms of the detection limit in total magnitude and magnitude difference of the systems under study. The MAMA system has the ability to detect some systems with magnitude differences larger than 3.5, although reliable astrometry could not be obtained on these objects. Reliable astrometry was obtained on a system of magnitude difference of 5.3 with the CCD system (Refer to PDF file for exact formulas).

Publication Date



© 1999 The American Astronomical Society.

It is a pleasure to thank David Sawyer at Kitt Peak for logistics help in using the telescope, Pat Patterson for help navigating the MAMA detector through US Customs in Tucson, and David Vaughnn for providing WIYN data necessary for our slit mask calibrations. We also thank Wendy Hughes, Craig Mackey, Gillian Rosenstein, and Bob Bode at Kitt Peak for their assistance in making these observations a success, and Brian Mason, for thoroughly reviewing the manuscript for errors. E. H. is grateful to William Hartkopf for providing up-to-date orbits for Bu 101 and Bu 151, to Constantine Deliyannis for helpful discussions regarding HR 7061, and to Imants Platais, for guidance on the M39 cluster binaries.

This work was funded through NSF support of Yale astrometry projects, NSF/IUCRC and NYCAT support of the sensor research effort at RIT, and a grant from the Fund for Astrophysical Research.

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