Infrared Speckle Observations of Binary Stars at the 6-m Telescope

Speckle observations of binary stars were performed in the 900–1600 nm infrared range at the 6‒m telescope using the commercially available CCD camera SWIR Snake-640 with InGaAs 640 × 512 pixels sensitive area. Peltier cooling of the sensor allows reaching –30°C temperature of the CCD. The thermal noise of the CCD remains significantly high under such temperature. That limits the speckle interferometric application of the camera to approximately 9th magnitude under moderate seeing conditions. To estimate other characteristics of the camera for interferometric application in the near-IR, we used it to measure separations, position angles and magnitude differences of some well-studied binary stars. Diffraction-limited angular resolution was achieved for each of the reconstructed images.