A simple camera with electron-multiplication CCD, fast frame rate, and pixel scale of 15 mas is described. This instrument was tested at the SOAR 4-m telescope in speckle interferometry regime. The data were processed by the standard speckle algorithm permitting to derive binary-star parameters. We observed 29 objects with separations from 21 mas to 1. 32, mostly southern binaries with known orbits. Some pairs require orbit revision. Two spectroscopic binaries HIP 9631 and HIP 11072 and the astrometric binary κ For are resolved for the first time, three objects were unresolved.

Bright single and binary stars were observed at the 4.1-m telescope with a fast electronmultiplication camera in the regime of partial turbulence correction by the visible-light adaptive optics system. We compare the angular resolution achieved by simple averaging of AO-corrected images (long-exposure), selection and re-centering (shift-and-add or "lucky" imaging) and speckle interferometry. The effect of partial AO correction, vibrations, and image post-processing on the attained resolution is shown. Potential usefulness of these techniques is evaluated for reaching the diffraction limit in ground-based optical imaging. Measurements of 75 binary stars obtained during these tests are given and objects of special interest are discussed. We report tentative resolution of the astrometric companion to ζ Aqr B. A concept of advanced high-resolution camera is outlined.

The adaptive module of the 4.1-m SOAR telescope, SAM, corrects ground-layer turbulence using a UV laser guide star. It has been commissioned in 2013 and it is in regular science operation since 2014. SAM works with the CCD imager covering a 3 ′ field or with the speckle camera. It operates routinely and stably, delivering resolution in the I band equal to the free-atmosphere seeing. This paper describes the SAM system as a whole, providing essential reference for its users and technical information of interest to instrumentalists. Operation of the instrument, its performance, and science projects done with SAM so far are reviewed.

No abstract

No abstract