Deferred charge measurements, and effects on serial covariance and variance. The three plots refer to channel 10 only, after linearity correction. Top: content of the first serial overscan pixel as a function of flat level (data points and a spline fit). Middle: first serial correlation as a function of flat level, before and after placing the charge back, that is, before and after deferred charge correction. Bottom: same as middle, but for the variance. In Fig. 3, there is no obvious distortion of the variance curve after linearity correction because channel 8 is essentially free of deferred charge.