Detailed schedule of changes

The schedule of changes below details the dates at which modifications were carried out at WFI which can affect the flat fields and other properties of the instrument. Data in one configuration should not be reduced with calibrations from other. This is particularly true for flat fields and for zero point maps.

By far the large effect occurred at Configuration 7, as the velvet appears to have reduced the light concentration problem by a factor of two. There are other changes not noted above as they can be found in the headers of the images: the CCD operation temperature was has varied between 167K and 169K in several occasions.