First speckle interferometric measurements at the Observatório do Pico dos Dias of the Laboratório Nacional de Astrofísica

In this paper we present the first speckle interferometric measurements of binary stars performed at the Observatório do Pico dos Dias of the Laboratório Nacional de Astrofísica in Brazil, using the 1.60 m Perkin-Elmer telescope. In order to carry out these observations, we had to perform an opto-mechanical modification to Camera 1 of the 1.60 m to meet the specifications of the observational programme. We focused our efforts on objects from the Washington Double Star Catalogue that were obtained during four observing runs allocated in 2017 and 2018. Among these objects, we have been interested in performing a follow-up observation of double stars discovered by the Hipparcos mission. We report here 464 astrometric measurements of 139 pairs, with angular separations ranging from 0.09 to 6.36 arcsec, including 361 systems with separations smaller than 1 arcsec. We estimated a mean error in separation of 15 mas and 1.2° in position angle. We confirmed 15 double stars discovered by Hipparcos, as well as four new pairs observed in previously known binaries turning them into triple systems, three of which have separations smaller than 0.16 arcsec. With these observations we introduce a new instrument to the astronomical community available at the Observatório do Pico dos Dias, capable of identifying relatively bright binaries, with angular separation very close to the resolution power of the telescope.