Speckle observations of 145 double stars and suspected double stars are presented and discussed. On the basis of multiple observations, a total of 280 position angle and separation measures are determined, as well as 23 high-quality nondetections. All observations were taken with the (unintensified) Rochester Institute of Technology fast-readout CCD camera mounted on the Lowell-Tololo 61 cm telescope at the Cerro Tololo Inter-American Observatory during 1999 October. We find that the measures, when judged as a whole against ephemeris positions of binaries with very well-known orbits, have root mean square deviations of (1.8+/- 0.3) degrees in position angle and (13+/-2) mas in separation. Eleven double stars discovered by Hipparcos were also successfully observed, and the change in position angle and/or separation since the Hipparcos observations was substantial in three cases (Refer to PDF file for exact formulas).

Publication Date



© 2000 The American Astronomical Society

We are grateful to R. Millis of Lowell Observatory for his support of this project ; C. Enterline, O. Saa, and D. Maturana of CTIO for their help before and during the observing run; R. Argyle of the Institute for Astronomy, Cambridge, UK, for advice on the target list ; R. Easton of RIT for a timely loan of equipment; and the referee for comments regarding a few objects in Table 2.

This work was funded by a grant from NASA administered by the American Astronomical Society and JPL subcontract 1201846 from the Preparatory Science Program for the Space Interferometry Mission.

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