The AOC (Adaptive Optics at Calern) project is an adaptive optics bench being installed on one of the two 1-m telescopes of C2PU (Centre Pédagogique Planète Univers), situated in the Calern observatory, Observatoire de la Côte d’Azur, near Nice (France). AOC is installed at the Coudé focus of the telescope, and aims at working in the visible and near-infrared wavebands. The system is designed to work both in a standard stellar mode and in a more innovative planetary mode. Various visible and near-infrared outputs are provided, so that AOC can be used upstream of a number of scientific instruments. Early scientific applications are, on the one hand, development of post-AO short-exposure processing techniques (when used in the framework of the HiPIC project up to ∼1600 nm), and, on the other hand, Jupiter oscillations (when used upstream of the JIVE/JOVIAL instrument at 519.6 nm). In addition to testing other concepts for imaging and interferometry, the facility will also be used for academic purposes, for instance in the framework of the Master program MAUCA. In this article we present the current status of the instrument, and in particular regarding the numerical modelling studies of its planetary wavefront sensing mode, with application to Mars and Jupiter.
We recently proposed a new lucky imaging technique, the Power Spectrum Extended (PSE), adapted for image reconstruction of short-exposure astronomical images in case of weak turbulence or partial adaptive optics correction. In this communication we show applications of this technique to observations of about 30 binary stars in H band with the 1m telescope of the Calern C2PU observatory. We show some images reconstructed at the diffraction limit of the telescope and provide measurements of relative astrometry and photometry of observed couples.
We propose, in the framework of high angular resolution imaging, a new image reconstruction technique denoted as Power Spectrum Extended (PSE). This method allows to perform the reconstruction of point-like and extended objects from a series of short-exposure frames, and is well adapted to post-adaptive optics images and/or small diameter telescopes. The algorithm works in the Fourier domain. It combines information from the average power spectrum of images with phase information estimated from an ad hoc shift-and-add process. It can be used together with a Lucky Imaging selection algorithm. It gives very encouraging results, even on very extended objects (larger than the isoplanatic angle) and at low light level (photon counting). In this communication, we present results obtained on astronomical objects as well as artificial satellites. We also show a comparison of performance with a reference Lucky Imaging technique.
The Very Large Telescope Interferometer Auxiliary Telescopes will soon be equipped with an adaptive optics system called NAOMI. The corrective optics deformable mirror is the commercial DM241 from ALPAO. Being part of an interferometer operating from visible to mid-infrared, the DMs of NAOMI face several challenges (high level of reliability, open-loop chopping, piston-free control, WFS/DM pupil rotation, high desired bandwidth and stroke). We here describe our extensive characterization of the DMs through measurements and simulations. We summarize the operational scenario we have defined to handle the specific mirror properties. We conclude that the ALPAO DMs have overall excellent properties that fulfill most of the stringent requirements and that deviations from specifications are easily handled. To our knowledge, NAOMI will be the first astronomical system with a command in true Zernike modes (allowing software rotation), and the first astronomical system in which a chopping is performed with the deformable mirror (5” sky, at 5 Hz).
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