Abstract: An optical system has a rotary scanning mirror, an optical instrument and an optical image rotation device. The rotary scanning mirror receives an incident beam of rays and returns an input beam along a first axis. The optical instrument receives the input beam from the scanning mirror and returns an output beam parallel to the input beam along a second axis in a direction opposite to the input beam towards the optical rotation device. The optical image rotation device is positioned on the second axis and receives the output beam. The scanning mirror has an axis of rotation aligned on the first axis. The optical image rotation device has an axis of rotation aligned on the second axis. The optical system comprises a common driving device for rotationally driving the optical image rotation device and the scanning mirror about their respective rotation axes.

Abstract: An optical system has a rotary scanning mirror, an optical instrument and an optical image rotation device. The rotary scanning mirror receives an incident beam of rays and returns an input beam along a first axis. The optical instrument receives the input beam from the scanning mirror and returns an output beam parallel to the input beam along a second axis in a direction opposite to the input beam towards the optical rotation device. The optical image rotation device is positioned on the second axis and receives the output beam. The scanning mirror has an axis of rotation aligned on the first axis. The optical image rotation device has an axis of rotation aligned on the second axis. The optical system comprises a common driving device for rotationally driving the optical image rotation device and the scanning mirror about their respective rotation axes.

Abstract: A spectrophotometer incorporating an interferometer and a dispersive system is adapted to have an enlarged inlet field without degrading its spatial resolution. To this end, spectral data deduced horn measurements performed by means of the interferometer are transferred into spectral data deduced from measurements per formed by means of the dispersive system. Such spectrophotometer makes it possible to scan an observation field quickly, and is compatible with use on board a satellite.

Abstract: A sampling spectrophotometer comprising an interferometer is used for performing a spectral analysis of light produced by a source. The sampling is adapted for eliminating uncertainty in the frequencies that are associated with spectral components deduced from an interferogram. Preferably, the interferometer is of Michelson type, and is equipped with at least one staircase mirror in one of the two optical paths. Elementary reflecting strips of the staircase mirror can then be offset with respect to one another according to a variable step.

Abstract: An optical system including a telescope and a principal pointing device for selecting a direction of observation is disclosed. The system furthermore includes at least one secondary pointing device arranged ahead of a part of the entrance of the telescope and oriented fixedly with respect to the principal pointing device. A set of photodetectors records a secondary image formed by the telescope from light rays directed by the secondary pointing device toward the entrance of the telescope The secondary image makes it possible to accurately determine the direction of observation.

Abstract: A spectrophotometer incorporating an interferometer and a dispersive system is adapted to have an enlarged inlet field without degrading its spatial resolution (?yi). To this end, spectral data deduced from measurements performed by means of the interferometer are transferred into spectral data deduced from measurements performed by means of the dispersive system. Such spectrophotometer makes it possible to scan an observation field quickly, and is compatible with use on board a satellite.

Abstract: A sampling spectrophotometer comprising an interferometer is used for performing a spectral analysis of light produced by a source. The sampling is adapted for eliminating uncertainty in the frequencies that are associated with spectral components deduced from an interferogram. Preferably, the interferometer is of Michelson type, and is equipped with at least one staircase mirror in one of the two optical paths. Elementary reflecting strips of the staircase mirror can then be offset with respect to one another according to a variable step.

Abstract: An optical system with variable pointing comprises a telescope and a principal pointing device selecting a direction of observation. The system furthermore comprises at least one secondary pointing device arranged ahead of a part of the entrance of the telescope and oriented fixedly with respect to the principal pointing device. A set of photodetectors records a secondary image formed by at least a part of the telescope from light rays directed by the secondary pointing device toward the entrance of the telescope. The secondary image makes it possible to accurately determine the direction of observation.

Abstract: The telescope includes at least one primary concave mirror (MI) for receiving an incoming image and relay optics for enlarging the image reflected by the primary mirror. The relay optics comprise a secondary mirror (M2) and a tertiary mirror (M3), each having a central aperture (12, 13) and each being positioned coaxially with the primary mirror (M1). The secondary mirror (M2) receives the image reflected by the primary mirror (M1) through the central aperture (13) of the tertiary mirror (M3). The tertiary mirror (M3), positioned close to the focal plane of the primary mirror (M1), receives the image reflected by the secondary mirror (M2) and reflects that image through the central aperture of the secondary mirror (M2).