Since 1885 the additional letter notation has been used, even if there was only one supernova discovered that year (e.g. SN 1885A, SN 1907A, etc.) — this last happened with SN 1947A.
從1885年開始採用字母命名，即使那一在只發現一顆超新星（如SN 1885A、SN 1907A等等） －最後一次是1947年的SN 1947A。