Measurements of visual binaries with EMCCD cameras and the Nice 76-cm refractor in 2009-2010

Description

We present relative astrometric and photometric measurements of visual binaries made in 2009-2010, with the 76-cm refractor of Côte d'Azur Observatory and a pair ofsensitive EMCCD ANDOR cameras. Ourobserving list consists of optical pairs and binaries whoseorbital motion is still uncertain. Three differenttechniques were used for obtaining measurements: Lucky Imaging, Speckle Interferometry and the Direct Vector Autocorrelation method. From the 2050 observationsof double stars that we performed, we obtained1652 new measurements of the relative position of 1792 objects, with angular separations in the range 0′′.1— 14′′.1. The average accuracy is estimated at 0′′.02 for the angular separations and 0◦.6 for the positionangles. We managed to observe faint systems (mV≈12) with large magnitude difference (up to ∆mV≈5).We have thus been able to measure many systems containing reddwarf stars that had been poorly monitoredsince their discovery. We also measured the difference of magnitude of the two components of 1143 objectswith an estimated error of 0.2 mag.

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