ZAMPIERI, LucaLucaZAMPIERIBURTOVOI, ALEKSANDRALEKSANDRBURTOVOIFIORI, MICHELEMICHELEFIORINaletto, GiampieroGiampieroNalettoSPOLON, ALESSIAALESSIASPOLONBarbieri, CesareCesareBarbieriPAPITTO, ALESSANDROALESSANDROPAPITTOAMBROSINO, FilippoFilippoAMBROSINO2021-02-222021-02-2220190035-8711http://hdl.handle.net/20.500.12386/30506We report the first detection of an optical millisecond pulsar with the fast photon counter Aqueye+ in Asiago. This is an independent confirmation of the detection of millisecond pulsations from PSR J1023+0038 obtained with SiFAP at the Telescopio Nazionale Galileo. We observed the transitional millisecond pulsar PSR J1023+0038 with Aqueye+ mounted at the Copernicus telescope in 2018 January. Highly significant pulsations were detected. The rotational period is in agreement with the value extrapolated from the X-ray ephemeris, while the time of passage at the ascending node is shifted by 11.55 ± 0.08 s from the value predicted using the orbital period from the X-rays. An independent optical timing solution is derived over a baseline of a few days that has an accuracy of ∼0.007 in pulse phase (∼12 μs in time). This level of precision is needed to derive an accurate coherent timing solution for the pulsar and to search for possible phase shifts between the optical and X-ray pulses using future simultaneous X-ray and optical observations.STAMPAenArticle10.1093/mnrasl/slz0432-s2.0-85073066839000482695700022http://arxiv.org/abs/1903.08930v1https://academic.oup.com/mnrasl/article/485/1/L109/54205032019MNRAS.485L.109ZFIS/05 - ASTRONOMIA E ASTROFISICA