@article{10902/13824, year = {2016}, url = {http://hdl.handle.net/10902/13824}, abstract = {Images of stars adopt shapes far from the ideal Airy pattern due to atmospheric density fluctuations. Hence, diffraction-limited images can only be achieved by telescopes without atmospheric influence, e.g. spatial telescopes, or by using techniques like adaptive optics or lucky imaging. In this paper, we propose a new computational technique based on the evaluation of the COvariancE of Lucky Images (COELI). This technique allows us to discover companions to main stars by taking advantage of the atmospheric fluctuations. We describe the algorithm and we carry out a theoretical analysis of the improvement in contrast. We have used images taken with 2.2-m Calar Alto telescope as a test bed for the technique resulting that, under certain conditions, telescope diffraction limit is clearly reached.}, organization = {This research was supported by the Ministerio de Economía y Competitividad under project FIS2012-31079 and the Fundación Séneca of Murcia under projects 15419/PI/10 and 15345/PI/10.}, publisher = {Oxford University Press}, publisher = {Monthly Notices of the Royal Astronomical Society, 2016, 455(3), 2765-2771}, title = {Covariance of lucky images for increasing objects contrast : diffraction-limited images in ground-based telescopes}, author = {Pérez Cagigal, Manuel and Valle Herrero, Pedro José and Colodro Conde, Carlos and Villó Pérez, Isidro and Pérez Garrido, Antonio}, }