Achromatic interfero coronagraphy^*

II. Effective performance on the sky

¹ Observatoire de la Côte d'Azur, Dpt. Fresnel, UMR-CNRS 6528, BP. 4229, 06304 Nice Cedex 04, France
² Observatoire de la Côte d'Azur, Dpt. Fresnel, UMR-CNRS 6528, Av. Copernic, 06130 Grasse, France
³ John Hopkins University, Baltimore, MD 21218, U.S.A.
⁴ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, U.S.A.
⁵ Office National de Recherche Aérospatiale, 29 avenue de la Division Leclerc, 92320 Châtillon, France

Send offprint request to: P. Baudoz, e-mail: baudoz@obs-nice.fr

Received: 28 October 1999
Accepted: 9 May 2000

Abstract

We report on the first observation run with the Achromatic Interfero Coronagraph (AIC) developed at Observatoire de la Côte d'Azur, France. Observations took place during Fall 97 at Observatoire de Haute Provence, France, with the 1.52 m telescope equipped at that time with adaptive optics. The Achromatic Interfero Coronagraph (AIC) is an imaging device providing the extinction of a star so as to detect and to image faint features of its close environment. Extinction results from a destructive interference process. Morphological features located as close to the star as the first angular Airy ring can be detected, thus breaking a limitation of the classical Lyot coronagraphs. The working spectral band was K. Observation results demonstrate the validity of the AIC approach with ground-based telescopes and illustrates close-sensing capabilities. After a short reminding of the principle of AIC, conditions of observations are reported and first results are discussed. Finally, limitations are evaluated and expected results are compared with effective performance.