ALFOSC CCD14 with CCD3COM controller
Using amplifier D the the columns 1-50 are prescan, 51-196 vignetting,
197-2037 imaging area, 2038-2098 vignetting, 2099-2148 overscan.
In y-direction lines 1-123 are vignetted, 124-1964 is the imaging area,
1964-2064 are vignetted and 2065-2102 are overscan pixels.
The field of view of ALFOSC is vignetted by the aperture wheel
in x roughly from columns 50 to 196 and from 2038 to 2098.
In y the vignetting is roughly from line 40 to 163 and from line 2003 to 2100.
Note these y-values are for amplifier A.