NGC 1275 light curve between August 2010 and February 2011 above an energy threshold of 100 GeV, and with a month time-scale binning. No hints of variability are seen in the data. The dashed horizontal line represents the constant function resulting from the fit to the data. For the December 2010, January 2011, and February 2011 data, the upper limits on the flux above 100 GeV for a spectral index of Γ =  −4.0 (calculated using the Rolke et al. 2005 method with a confidence level of 95%, and a total systematic uncertainty of 30%) are also shown (open dashed arrows).