In 2005 and 2006 , the MAGIC telescope has observed very high energy gamma-ray emission from the distant BL Lac object PG 1553+113 .
The overall significance of the signal is 8.8 ~ { } \sigma for 18.8 h observation time .
The light curve shows no significant flux variations on a daily time-scale , the flux level during 2005 was , however , significantly higher compared to 2006 .
The differential energy spectrum between \sim 90 GeV and 500 GeV is well described by a power law with photon index \Gamma = 4.2 \pm 0.3 .
The combined 2005 and 2006 energy spectrum provides an upper limit of z = 0.74 on the redshift of the object .