Speckle observations with PISCO in Merate - IX. Astrometric measurements of visual binaries in 2008

Abstract

We present relative astrometric measurements of visual binaries, made in 2008 with the Pupil Interferometry Speckle camera and Coronagraph (PISCO) at the 102 cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our sample contains orbital couples as well as binaries whose motion is still uncertain. We obtained 240 new measurements of 237 objects with angular separations in the range 0.15-4.6 arcsec, and an average accuracy of 0.014 arcsec. The mean error on the position angles is 0. • 6. Most of the position angles were determined without the usual 180 • ambiguity with the application of triple-correlation techniques and/or by inspection of the long integration files.We have found a new component in ADS 11074. This component was not fully resolved in our previous observations of 2006, but it was clearly separated with the observations presented here.We also present the new revised orbits we have computed for ADS 11468, 13850 and 16057, for which our measurements lead to large residuals with the last published orbits. For ADS 13850, we propose to extend the quadrant correction that was previously used by the other authors to the first measurements made before 1930. In this way, we obtain an orbit with a longer period which leads to a much more plausible value for the total mass of the system.

Speckle observations with PISCO in Calern (France): I. Astrometric measurements of visual binaries in 2015–2016

“…The purpose of this article is to contribute to a better knowledge of the apparent relative motion of long‐period binaries so that very accurate orbits could be determined in the future and fundamental parameters such as stellar masses could be inferred from them. This article opens up a new series that will be the counterpart of the series of articles that have reported the results of observations with PISCO in Brera Astronomical Observatory (Merate, Italy): Scardia et al , , , , Prieur et al , Scardia et al , Prieur et al , Scardia et al , Prieur et al , Scardia et al , Prieur et al , Scardia et al , Prieur et al , Scardia et al , Prieur et al , and Scardia et al , herein: Papers I to XVI. The focal instrument PISCO (Prieur et al ) was developed at Observatoire Midi‐Pyrénées (France) and first used at Pic du Midi observatory (France) from 1993 to 1998.…”

Speckle observations with PISCO in Merate (Italy): XIV. Astrometric measurements of visual binaries in 2013 and new orbits for ADS 1097, 5871, 7203, 7775, 9378, 9578, and 11186

“…It is the fourteenth of a series whose purpose is to contribute to the determination of binary orbits (Scardia et al 2005(Scardia et al , 2006(Scardia et al , 2007(Scardia et al , 2008aPrieur et al 2008;Scardia et al 2009;Prieur et al 2009;Scardia et al 2010;Prieur et al 2010;Scardia et al 2011;Prieur et al 2012;Scardia et al 2013;Prieur et al 2014, herein Papers I to XIII). The focal instrument PISCO was developed at Observatoire Midi-Pyrénées (France) and first used at Pic du Midi from 1993 to 1998.…”

Speckle observations with PISCO in Merate: X. Astrometric measurements of visual binaries in 2009

“…It is the tenth of a series (Scardia et al 2005(Scardia et al , 2006(Scardia et al , 2007(Scardia et al , 2008aPrieur et al 2008;Scardia et al 2009;Prieur et al 2009;Scardia et al 2010;Prieur et al 2010, herein: Papers I to IX), whose purpose is to contribute to the determination of binary orbits. PISCO was developed at Observatoire Midi-Pyrénées (France) and first used at Pic du Midi from 1993 to 1998.…”