4327 20200213143107.0 CTALK-2019-0138 Lefèvre, Laure VAL-U-SUN: Goals and progresses 2019 2019-08-20 BR/ 165/ A3/VAL-U-SUN STCE Mathieu, Sophie ISSI recalibration of the sunspot number laure.lefevre@observatoire.be Invited CTALKCONT