V405 Vul possible superoutburst YYYYMMDD(UT) mag observer 20180309.8672 155c (Yutaka Maeda) 20180310.8318 <149c (Yutaka Maeda) 20180311.8249 <144c (Yutaka Maeda) 20180314.8287 144c (Yutaka Maeda) 20180316.7942 148c (Yutaka Maeda)