[Previous] | [Session 5] | [Next]
E. P. Horch, Z. Ninkov (RIT), R. D. Meyer, W. F. van Altena (Yale U.)
The RIT-Yale Tip-tilt Speckle Imager (RYTSI) is a unique speckle imaging system that can use any large-format CCD as the image recording device. Short exposure images are created by moving the star image in a rapid step-and-expose pattern that covers the entire area of the chip. When this process is completed, all of the recorded images are read out together. The image movement is accomplished with a tip-tilt mirror system enclosed in a compact optics package that sits between the telescope and the CCD system. When used with the RIT 2048x2048-pixel CCD camera, approximately 256 (diffraction-limited) speckle images can be recorded in a 16x16 grid per full-frame read at a 4-m class telescope. As large-format, high-quantum-efficiency astronomy CCDs continue to improve in terms of readout speed and read noise, they compete very favorably with more traditionally used intensified-CCD (ICCD) systems in terms of the signal-to-noise ratio obtainable per frame in speckle imaging applications. In addition, the linear performance of CCDs appears to allow for the possibility of reliable diffraction-limited differential photometry1, something that has proved extremely difficult to do with ICCDs. Construction of RYTSI is now nearing completion at RIT, and the module is scheduled for use at the WIYN 3.5-m telescope for the first time later this year. The design and performance are discussed, as well as the future observational program with RYTSI at WIYN.
Funding for this work has been provided by NSF grant 9731165.
1 Horch, E., Ninkov, Z., & Franz, O. G. 2001, AJ, 121, 1583