Correction de la dispersion atmosphérique dans l’imagerie par les grands télescopes et les interféromètres astronomiques

• Published in: Comptes rendus. Physique Vol. 23; no. S1; pp. 345 - 364
• Main Authors: Koechlin, Laurent, Dettwiller, Luc
• Format: Journal Article
• Language: English
• Published: Académie des sciences 01.04.2023
• Subjects: Dispersion; Haute résolution angulaire; Interféromètre achromatique de Sinton; Interféromètres astronomiques; Interférométrie des tavelures; Prismes de Risley
• ISSN: 1878-1535
• DOI: 10.5802/crphys.112

The very large telescopes and the various optical interferometers provide access to unparalleled angular resolutions and provide scientific data of primary importance, but at the price of instrumental constraints that require complex equipment. The correction of the atmospheric dispersion (i.e. of the variation of the air refractive index versus the wavelength) is one of these constraints. This dispersion comes in three forms: the angular dispersion (the image of a star is spread out into a small spectrum); the dispersion in optical path difference in an interferometer (for the correction of which we propose a new technique to our knowledge); and the lateral dispersion that is related to the apparition of colours in the scintillation. The question of stabilizing the optical path difference in optical interferometers is also raised.