A speckle interferometer for use at the Cassegrain focus of large telescopes has been constructed and used to observe binary star systems on the 2.5 m Isaac Newton telescope in England. The instrument has a four-stage, magnetically focused EMI image intensifier with a maximum light gain in excess of 10<sup>6</sup>. , good resolution, and low background noise. The final images are recorded on 16mm cine film. Both analog optical and digital analyses have been carried out. The digital analysis enables the transfer function of the speckle method to be found and divided into the image power spectrum. Examples are given of experimental results. Binary star separations have been measured for stars as close as 0.1 arc sec and as faint as magnitude 6.
© 1976 Optical Society of America
D. R. Beddoes, J. C. Dainty, B. L. Morgan, and R. J. Scaddan, "Speckle interferometry on the 2.5 m Isaac Newton telescope," J. Opt. Soc. Am. 66, 1247-1251 (1976)