V405 Vul superoutburst? YYYYMMDD(UT) mag observer 20180221.8668 <152c (Yutaka Maeda) 20180222.8023 <148c (Yutaka Maeda) 20180223.8194 <154c (Yutaka Maeda) 20180226.7971 143c (Yutaka Maeda)