**LWP** - The LWP camera appears to have two behavioral
trends in sensitivity degradation (Teays and Garhart 1990). The division
occurs at approximately 1984.5, which corresponds to the time this
camera became the default camera. Post-1984.5 data are corrected using a
linear fit (Bevington 1969) to the ratios in that time period, while
images taken prior to 1984.5 are corrected using a linear interpolation
between each pre-1984.5 degradation ratio. The fluxes of corrected
pre-1984.5 data will be less accurate than the fluxes of corrected
post-1984.5 data due to the higher uncertainty in the degradation ratios
for the early data. Fortunately little science data (except for
calibration images) were taken using this camera during the pre-1984.5
time period, so the impact on the entire archive is minimal.

**LWR** - As is the case with the LWP camera, the LWR
exhibits two trends with the dividing point occurring at approximately
the same time. However, since the LWR is a closed data set, the binned
degradation ratios were fit with a fourth-order polynomial covering the
entire time period.

**SWP** - The SWP sensitivity degradation for the
post-1979.5 epoch is represented by a linear relationship. The 1978.5 to
1979.5 epoch degradation ratios, which exhibit a behavior unlike the
post-1979.5 epoch, were fit using a linear interpolation between each
discrete point (Garhart 1992c).