ASASSN-15sn superoutburst Known SU UMa star. YYYYMMDD(UT) mag observer 20230421.751 <174C (Mitsutaka Hiraga) 20230422.5123 <18.033g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230425.5005 <18.081g (ASAS-SN Sky Patrol Photom. DB (Hart+2023; Shappee+2014)) 20230427.4244 15.930zg (ZTF Alert DC mag (Masci+ 2019)) 20230427.4697 15.964zr (ZTF Alert DC mag (Masci+ 2019)) 20230501.4274 15.769zr (ZTF Alert DC mag (Masci+ 2019)) 20230502.8005 151c (Yutaka Maeda)