MKN421 brighter YYYYMMDD(UT) mag observer 20021218.242 129 (Eddy Muyllaert) 20021229.080 130 (Jose Ripero) 20021230.856 130 (Hiroshi Itoh) 20030103.985 129 (Jose Ripero) 20030104.008 125 (Gary Poyner)