Figure 2.8: The modulation coefficient M1 as observed over the mission, for the
two fields of view. Most of the discontinuities are the result of refocusing, others are
caused by temporary thermal-control problems. The red dots relate to the preceding,
the green dots to the following field of view. These data are for the centre of each
field of view, and for a colour index of (V − I)C = 0.5.