Photometer Characterization

Today we characterized our photometers. We took 3 photometers that were built by three different people outside and read the voltages from various angles to the sun for each. We got the following data.
Orientation is from the vertical to the sun in degrees.All voltages are in Volts.
Orientation  V1   V2   V3
O to SunVrichVmiloVreed
  70 0.49 0.45 0.86
  60 0.62 0.59 1.04
  50 0.72 0.764 1.13
  40 0.86 1       1.19
  30 1.04 1.13  1.22
  20 1.18 1.2     1.2
  10 1.2 1.21
    0 1.29 1.28  1.26