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).
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Astronomical Journal 117N1 (1999) 548-561
RIT – Main Campus