The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument aims at detecting extremely faintsources (giant extrasolar planets) in the vicinity of bright stars1. Such a challenging goal requires the use of a very-highorderperformance Adaptive Optics [AO] system feeding the scientific instruments with a quasi-perfect flat wave frontcorrected from all the atmospheric turbulence and internal defects. This AO system, called SAXO (Sphere Ao foreXoplanet Observation) is the heart of the instrument, a heart beating 1200 time per second and providing unprecedentedimage quality for a large ground based telescope at optical/near infrared wavelength. We will present the latest resultsobtained on-sky, demonstrating its exceptional performance (in terms of correction quality, stability and robustness) andtremendous potentiality for exoplanet discovery

The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument aims at detecting extremely faint1sources (giant extrasolar planets) in the vicinity of bright stars . Such a challenging goal requires the use of a very-high-order performance Adaptive Optics [AO] system feeding the scientific instruments with a quasi-perfect flat wave front corrected from all the atmospheric turbulence and internal defects. This AO system, called SAXO (Sphere Ao for eXoplanet Observation) is the heart of the instrument, a heart beating 1200 time per second and providing unprecedented image quality for a large ground based telescope at optical/near infrared wavelength. We will present the latest results obtained on-sky, demonstrating its exceptional performance (in terms of correction quality, stability and robustness) and tremendous potentiality for exoplanet discovery.

The SPHERE instrument (Beuzit, et al., 2010) is dedicated to the direct imaging of extra-solar planets. This kind of observation allows one to study the photons emitted by the planet’s atmosphere itself, or reflected by its surface. The search for bio-markers is therefore made possible. The SPHERE instrument has been installed and commissioned at VLT Paranal Observatory during 2014 and now routinely delivers high contrast images to the exoplanet community. This paper presents a study of the main actual limitation of the SPHERE instrument, as known as the Low Wind Effect [LWE]. This effect has been discovered on SPHERE during commissioning period. Its effect is a strong degradation of the instrument PSF, preventing instrument to perform high contrast imaging. It happens during particularly low wind conditions (below 1m/s at the telescope level) which happens one night out of five.