Speckle observation of visual double stars at Bosscha observatory

We present the result of visual double stars speckle observation in 2012, using 24 inch (60 cm) refractor at the Bosscha Observatory. The objects selected for this observation are calibration candidates, their separations range from 1–7 arc second, and they are located in both northern and southern hemisphere. Seeing effect due to the Earth atmospheric turbulence limits the resolution of ground-based telescopes. Seeing over Bosscha Observatory is generally 1–2 arc second, imposing a limit on visual double star separation below which the system cannot be resolved by long exposure imaging (longer than ∼ 50 ms). Speckle interferometry method is used to resolve double stars with separation below typical size of seeing effect. Series of images are captured in fast short-time exposures (∼ 50 ms) using CCD camera. The result of our first experiment shows that our system can be used to measure separation of 1.8 arc second, with Δm ≃ 1.