Estimated correlation coefficients for the ﹩\sim 10\% ﹩ of the off‐diagonal elements of the K‐correction covariance matrix that we can currently measure plotted against the difference between the two epochs. Here the ﹩z=0.8i_{\mathrm{M}\,}\mapsto B﹩ is shown. At this redshift the filters line up fairly well. Note that some of the correlation coefficients are greater than one, which is unphysical, and results from the fact that many of these bins have only one SN Ia in them.