CCF `LinCoord` holds the positions of distinct reference
points of the CCD's (at reference temperature) and the
directions in which the counting of `rawX` and `rawY`
increases. The size of each pixel is stored in CCF `MiscData`, and
also a thermal expansion coefficient.

Using these inputs, together with (`rawX,rawY`), the location of
each pixel can be given in focal plane coordinates as a function of
temperature. The shift of CCD's due to thermal contraction/expansion
is calculated such that each CCD is fixed with its center on the cold
bench (thermal expansion of Al), and the pixel-size is determined from
the thermal expansion coefficient of Si.

Michael Smith 2011-09-20