Microvariability Detection of Mrk 421

The BL Lac object Mrk 421 was observed in optical bands from 2009 April to 2012 May with the 1.0 m telescope at Weihai Observatory of Shandong University. Microvariability was analysed by C and F tests, but no significant microvariability was detected during our observations.Comment: 2 pages, 1 figur