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The Engineering Test Unit (ETU) of the Fine Guidance Sensor (FGS) for the James Webb Space Telescope (JWST) is currently in fabrication. Extensive modeling of the key FGS-Guider performance parameters has been used throughout the design process and continues to be used to evaluate the expected performance of the as-built instrument. A key parameter of interest is the expected Noise Equivalent Angle (NEA) provided by the FGS. The NEA will, in part, determine the ultimate image quality of the JWST Observatory. In this paper we use updated estimates of the End-oflife impact of contamination to present the current expected NEA performance of the FGS flight model. As component test data becomes available this data will be used as input to the FGS NEA performance model to assess the expected performance of the instrument.

International audience; The WIND imaging interferometer (WINDID was launched on the Upper Atmosphere Research Satellite (UARS) on September 12, 1991. This joint project, sponsored by the Canadian Space Agency and the French Centre National d'Etudes Spatiales, in collaboration with NASA, has the responsi- bility of measuring the global wind pattern at the top of the altitude range covered by UARS. WINDII measures wind, temperature, and emission rate over the altitude range 80 to 300 km by using the visible region airglow emission from these altitudes as a target and employing optical Doppler interferometry to measure the small wavelength shifts of the narrow atomic and molecular airglow emission lines induced by the bulk velocity of the atmosphere carrying the emitting species. The instrument used is an all-glass field-widened achromatically and thermally compensated phase- stepping Michelson interferometer, along with a bare CCD detector that images the airglow limb through the interferometer. A sequence of phase-stepped images is processed to derive the wind velocity for two orthogonal view directions, yielding the vector horizontal wind. The process of data analysis, including the inversion of apparent quantities to vertical profiles, is described.

We describe a procedure for reconstructing turbulence-degraded images using complex ratios of adjacent, spatial-frequency components.