One-Dimensional Telescope Aperture For Brightness And Velocity Speckle Interferometry Measurements

The use of a telescope with a "one dimensional" aperture (10 x 800 cm for example) is suggested for high angular speckle interferometry. In the image plane, the speckles are elongated in a direction perpendicular to the entrance pupil. For a given amount of atmospherical turbulence, a one-dimensional pupil gives a contrast gain in the high frequencies region compared to the circular objective having the same resolution limit. Associated with a spectroscope, a one-dimensional telescope allows the representation of the spatial-spectral plane with no loss of photons. This is obtained because the image of the telescope aperture is the entrance slit of the spectroscope. It permits precise, high resolution astronomical measurements as a function of wavelength as well as velocity speckle-interferometry at high level of photons with CORAVEL type experiments. The study of a domeless, altazimuthal mount, low-cost prototype of 4 cm x80 cm, intended for solar observations, is developed at the Nice Observatory.