RYTSI: The Rochester Institute of Technology–Yale Tip-Tilt Speckle Imager

We have constructed a new speckle imaging system that collects a large number of speckle patterns on the detector area of a large-format CCD. The system is called the RIT-Yale Tip-tilt Speckle Imager (RYTSI) because it uses two galvanometric scanning mirrors to tip and tilt each speckle pattern to a different location on the CCD chip. It therefore solves the bandwidth problem of using CCDs in speckle imaging in a unique way: the mirrors direct speckle patterns across the chip with millisecond accuracy, and the CCD is read out only when the chip is filled with patterns. The instrument was designed to accommodate a variety of detector formats, readout systems, and telescope plate scales; it was initially used at the WIYN Observatory in conjunction with an RIT (Rochester Institute of Technology) 2048 CCD. We present the design of the instrument and a sample of first results, which indicate that the instrument can be expected to recover, with high precision, both astrometric and photometric information for binary and multiple stars.