Characteristics and performances of an interferometric Doppler imager installed at the 188 cm telescope of Okayama Observatory

We describe the performances of a novel Doppler imager, aimed to detect acoustic oscillations and atmospheric dynamics at the surface of giant planets of the Solar System in the frame of the JOVIAL (Jovian Oscillations detection by Velocity Imaging At several Longitudes) project. The first JOVIAL instrument was installed on the 188cm telescope at Okayama branch of National Astronomical Observatory of Japan (NAOJ) in April 2019. This instrument is a part of a ground based network of three identical instruments installed on telescopes around the world for continuous observations. First observations of Jupiter with the JOVIAL instrument were achieved in June 2019. We describe the instrument principle, its design and the set-up at Okayama observatory, as well as the performances reached during the first observing run. We finally provide plans for future observations with the network.