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van Kooten, M. (author), Doelman, N.J. (author), Kenworthy, M. (author)Current high contrast imaging systems are limited at small angular separations, preventing the direct imaging of Earth-size exoplanets close to their host stars. One primary cause of this is the performance of the extreme adaptive optics (AO) system which is dominated by the servo-lag error at small angular separations. Prediction can be used to...conference paper 2017
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Mora, A. (author), Biermann, M. (author), Brown, A.G.A. (author), Busonero, D. (author), Carminati, L. (author), Carrasco, J.M. (author), Chassat, F. (author), Erdmann, M. (author), Gielesen, W.L.M. (author), Jordi, C. (author), Katz, D. (author), Kohley, R. (author), Lindegren, L. (author), Loeffler, W. (author), Marchal, O. (author), Panuzzo, P. (author), Seabroke, G. (author), Sahlmann, J. (author), Serpell, E. (author), Serraller, I. (author), van Leeuwen, F. (author), van Reeven, W. (author), van den Dool, T.C. (author), Vosteen, L.L.A. (author)The Gaia payload ensures maximum passive stability using a single material, SiC, for most of its elements. Dedicated metrology instruments are, however, required to carry out two functions: monitoring the basic angle and refocusing the telescope. Two interferometers fed by the same laser are used to measure the basic angle changes at the level...conference paper 2014
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Mora, A. (author), Vosteen, L.L.A. (author)The ESA Gaia spacecraft has two Shack-Hartmann wavefront sensors (WFS) on its focal plane. They are required to refocus the telescope in-orbit due to launch settings and gravity release. They require bright stars to provide good signal to noise patterns. The centroiding precision achievable poses a limit on the minimum stellar brightness...conference paper 2012
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TNO Industrie en Techniek (author), Vosteen, L.L.A. (author), Draaisma, F. (author), Werkhoven, W.P. (author), Riel, L.J.M. (author), Mol, M.H. (author), Den, O.G. (author)TNO developed a Wave Front Sensor (WFS) instrument for the GAIA mission. This Wave Front Sensor will be used to monitor the wave front errors of the two main telescopes mounted on the GAIA satellite, which may be corrected by a 5- degree of freedom (DOF) mechanism during operation. The GAIA-WFS will operate over a broad wavelength (450 to 900 nm...conference paper 2009