Infrared multiplex imagery. I - Properties, instrumentation and observations

Features of a multiplex encoding photometer (MEP) for high spatial resolution IR imagery of the inner regions of celestial objects are described, along with associated selection and composite data reduction schemes. The MEP has provided 32 x 32 x pixel images from the ESO 3.60 m telescope since 1977. A coding mask allows all pixels to be closed and provides for a perfect optical mutual transfer function. The coding is highly transparent to autocorrelation and Fourier transforms, so the speckle interferometry can be performed directly. The images are obtained with a 0.1 sec integration time for a 6.4 arcsec FOV, using J, H, K, L, and M filters. The fast acquisition times permit 20 Mbyte of data to be collected in 18 min.