Improvements on VLT/NaCo and AO Activities on Paranal

Thursday, 12 April 2012 11 a.m. — noon MST

AURA Lecture Hall

NOIRLab South Colloquia
Julien Girard (ESO & Gemini South Visiting Astronomer)

I will briefly present NaCo, the famous and versatile diffraction limited NIR imager and spectrograph at the Very Large Telescope (VLT). With NACO, ESO just celebrated 10 years of Adaptive Optics at the VLT. Since two years a substantial effort has been put in understanding and fixing issues that directly affect the image quality and the high contrast performances of the instrument: compensation of the non-common-path aberrations(NCPA, with help of Gemini AO experts) to recover the highest possible strehl ratios, repair of the infamous drift associated to pupil tracking - necessary for angular differential imaging (ADI) and sparse aperture masking interferometry (SAM). In the framework of our AO operations group on Paranal, the work accomplished on NACO will serve as reference for the next generation instruments on the VLT, especially the ones working at the diffraction limit and making use of ADI, a technique that allows to build median PSF references from the data and calibrate efficiently quasi-static aberrations. I will finish by showing pretty pictures and pretty nice results obtained with pretty original modes with NaCo.