BT CrB likely superoutburst UGSU+E YYYYMMDD(UT) mag observer 20230329.3247 19.011zg (ZTF Alert DC mag (Masci+ 2019)) 20230408.3995 17.269zg (ZTF Alert DC mag (Masci+ 2019)) 20230408.4348 17.351zr (ZTF Alert DC mag (Masci+ 2019)) 20230410.3453 17.103zg (ZTF Alert DC mag (Masci+ 2019)) 20230410.4020 17.183zr (ZTF Alert DC mag (Masci+ 2019)) 20230410.4025 17.143zr (ZTF Alert DC mag (Masci+ 2019))