MGAB-V500 likely superoutburst (suspected AM CVn) YYYYMMDD(UT) mag observer 20221111.2710 20.398zr (ZTF Alert DC mag (Masci+ 2019)) 20221113.1855 19.368zg (ZTF Alert DC mag (Masci+ 2019)) 20221115.2063 17.188zg (ZTF Alert DC mag (Masci+ 2019)) 20221115.2581 17.457zr (ZTF Alert DC mag (Masci+ 2019))