SPECKLE IMAGING WITH THE MAMA DETECTOR - PRELIMINARY-RESULTS

We report on the first successful speckle imaging studies using the St anford University speckle interferometry system, an instrument that us es a multianode microchannel array (MAMA) detector as the imaging devi ce. The method of producing high-resolution images is based on the ana lysis of so-called ''near-axis'' bispectral subplanes and follows the work of Lohmann et al. (1983). In order to improve the signal-to-noise ratio in the bispectrum, the frame-oversampling technique of Nakajima et al. (1989) is also employed. We present speckle imaging results of binary stars and other objects from V magnitude 5.5 to 11, and the qu ality of these images is studied. While the Stanford system is capable of good speckle imaging results, it is Limited by the overall quantum efficiency of the current MAMA detector (which is due to the response of the photocathode at visible wavelengths and other detector propert ies) and by channel saturation of the microchannel plate. Both affect the signal-to-noise ratio of the power spectrum and bispectrum.