Speckle interferometry at SOAR in 2016 and 2017

Abstract: The results of speckle interferometric observations at the 4.1 m SOAR telescope in 2016 and 2017 are given, totaling 2483 measurements of 1570 resolved pairs and 609 non-resolutions. We describe briefly recent changes in the instrument and observing method and quantify the accuracy of the pixel scale and position angle calibration. Comments are given on 44 pairs resolved here for the first time. Orbital motion of the newly resolved subsystem BU~83 Aa,Ab roughly agrees with its 36 year astrometric orbit proposed by J.~Dommanget. Most Tycho binaries examined here turned out to be spurious.