Dalessandro, EmanueleEmanueleDalessandroSARACINO, SaraSaraSARACINOORIGLIA, LiviaLiviaORIGLIAMarchetti, EnricoEnricoMarchettiFerraro, Francesco R.Francesco R.FerraroLanzoni, BarbaraBarbaraLanzoniGeisler, DouglasDouglasGeislerMauro, FrancescoFrancescoMauro2020-07-072020-07-07201697815106019870277-786Xhttp://hdl.handle.net/20.500.12386/26359Ground-based near-IR imagers assisted by Multi Conjugate Adaptive Optics (MCAO) systems are the technological frontier to obtain high-quality stellar photometry in crowded fields at the highest possible spatial resolution. The Gemini MCAO System (GeMS) feeding the Gemini South Adaptive Optics Imager (GSAOI) is the only facility of this kind currently available to the Community. We used a set of images obtained in the J and K<SUB>s</SUB> bands of the central regions of two Galactic bulge globular clusters (Liller 1 and NGC 6624) with GeMS/GSAOI, under significantly different atmospheric conditions. We characterized the performances of the system in terms of efficiency and uniformity of the Point Spread Function (PSF) over the field of view with varying seeing, airmass and tip-tilt star asterisms. We also compared the PSF performances of GeMS/GSAOI with the HST/ACS ones in the F606W and F814W bands.ELETTRONICOenConference paper10.1117/12.22309782-s2.0-85002335887000387429700167https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9909/1/GeMSGSAOI-performances-from-a-user-perspective/10.1117/12.2230978.full?SSO=12016SPIE.9909E..5VDFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation