  OI 090.4 was monitored on 21 nights from 2006 to 2012 for studying the
variability. Strong variations occurred during the past 6 years. The long-term
variability amplitude is consistent with previous results. Microvariability was
analyzed for 43 intra-night light curves. 30 out of 43 light curves showed
microvariability by C and F tests analysis.
