CCD MEASUREMENTS OF DOUBLE AND MULTIPLE STARS AT NAO ROZHEN AND ASV IN 2011. FIVE LINEAR SOLUTIONS

Abstract

Using the 2 m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 222 double or multiple stars were carried out during three nights in 2011. This is the sixth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. Also in 2011, using the 0.6 m telescope of the Serbian Astronomical Station on the mountain of Vidojevica, observations of 208 double or multiple stars were carried out during six nights. This is the first series of measurements of CCD frames of double and multiple stars obtained at this station. In this paper, we present the results for the position angle and angular separation for 337 pairs and residuals for 72 pairs with published orbital elements or linear solutions. These observations have angular separations in the range from 1.''37 to 172.''81, with a median angular separation of 7.''66. We also present the recalculated linear solutions for four pairs and one linear solution that has been calculated for the first time.