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Authors: A. La Camera, M. Carbillet, C. Olivieri, P. Boccacci, M. Bertero
Abstract: The Software Package AIRY (acronym for Astronomical Image Restoration in interferometrY) is a software tool designed to perform simulation and/or deconvolution of images of Fizeau interferometers as well as of any kind of optical telescopes. AIRY is written in IDL and is a Software Package of the CAOS Problem Solving Environment (PSE): it is made of a set of modules, each one representing a specific task. We present here the last version of the software, arrived at its sixth release after 10 years of development. This version of AIRY summarizes the work done in recent years by our group, both on AIRY and on AIRY-LN, the version of the software dedicated to the image restoration of LINC-NIRVANA (LN), the Fizeau interferometer of the Large Binocular Telescope (LBT). AIRY v.6.0 includes a renewed deconvolution module implementing regularizations, accelerations, and stopping criteria of standard algorithms, such as OSEM and Richardson-Lucy. Several modules of AIRY have been improved and, in particular, the one used for the extraction and extrapolation of the PSF. In addition, AIRY has modules dedicated to the simulation of interferometric images and utility modules for data reading, writing, and visualization. After a description of the implemented reconstruction methods and of the whole set of modules, we provide several example projects in order to give to the astronomical community a powerful tool for the preparation of the observations and for the real data deconvolution.

Rating: 35 user(s) have rated this article Average rating: 5.0
Posted by: andrea, on 10/1/2012, in category "2012"
Views: this article has been read 5905 times
Authors: A. La Camera, S. Antoniucci, M. Bertero, P. Boccacci, D. Lorenzetti, B. Nisini
Abstract: We report the results of a simulation and reconstruction of observations of a young stellar object (YSO) jet with the LINC-NIRVANA (LN) interferometric instrument, which will be mounted on the Large Binocular Telescope (LBT). This simulation has been performed in order to investigate the ability of observing the weak diffuse jet line emission against the strong IR stellar continuum through narrow band images in the H and K atmospheric windows. In general, this simulation provides clues on the image quality that could be achieved in observations with a high dynamic range. In these cases, standard deconvolution methods, such as Richardson-Lucy, do not provide satisfactory results: we therefore propose here a new method of image reconstruction. It consists in considering the image to be reconstructed as the sum of two terms: one corresponding to the star (whose position is assumed to be known) and the other to the jet. A regularization term is introduced for this second component and the reconstruction is obtained with an iterative method alternating between the two components. An analysis of the results shows that the image quality obtainable with this method is significantly improved with respect to standard deconvolution methods, reducing the number of artifacts and allowing us to reconstruct the original jet intensity distribution with an error smaller than 10%.

Rating: 10 user(s) have rated this article Average rating: 5.0
Posted by: andrea, on 10/1/2012, in category "2012"
Views: this article has been read 6064 times
Authors: Ralph Hofferbert; and other 67 co-authors (LINC-NIRVANA Team)
Abstract: LINC-NIRVANA (LN) is the near-infrared, Fizeau-type imaging interferometer for the Large Binocular Telescope (LBT) on Mt. Graham, Arizona, USA (3267m of elevation). The instrument is currently being built by a consortium of German and Italian institutes under the leadership of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, Germany. It will combine the radiation from both 8.4m primary mirrors of LBT in such a way that the sensitivity of a 11.9m telescope and the spatial resolution of a 22.8m telescope will be obtained within a 10.5arcsec x 10.5arcsec scientific field of view. Interferometric fringes of the combined beams are tracked in an oval field with diameters of 1 and 1.5arcmin. In addition, both incoming beams are individually corrected by LN’s multi-conjugate adaptive optics (MCAO) system to reduce atmospheric image distortion over a circular field of up to 6arcmin in diameter. This paper gives a comprehensive technical overview of the instrument comprising the detailed design of LN’s four major systems for interferometric imaging and fringe tracking, both in the NIR range of 1 - 2.4µm, as well as atmospheric turbulence correction at two altitudes, both in the visible range of 0.6 - 0.9µm. The resulting performance capabilities and a short outlook of some of the major science goals will be presented. In addition, the roadmap for the related assembly, integration and verification (AIV) process will be discussed. To avoid late interface-related risks, strategies for early hardware as well as software interactions with the telescope have been elaborated. The goal is to ship LN to the LBT in 2014.

Rating: 940 user(s) have rated this article Average rating: 5.0
Posted by: andrea, on 12/14/2012, in category "2012"
Views: this article has been read 8551 times