Speckle Observations of Binary Stars with the MAMA Detector

Abstract

We have made two sets of speckle observations of binary stars with the Multi-Anode Microchannel Array (MAMA) detector. Our observing system is a true photon counting imaging device which records the arrival time of every detected photon. We present speckle autocorrelation analyses of five binary systems, two observed with the 3.6-m telescope at the European Southern Observatory and three observed with the 40-in reflector at Lick Observatory. These five systems represent a wide variation in separation and magnitude difference that indicate that the MAMA detector is capable of recording high quality speckle data at extremely low count rates and can recover image features very near the diffraction limit of the telescope. In one case, only 10 photons per frame were recorded for the dim companion of the system, and in another case, a separation of 0″.157±0″.031 was derived for a system observed with the 40-in telescope where the diffraction limit is about 0″.125. Future prospects for this system are discussed.