Flux variability detected in 13 of the 29 knots. The deviations from average flux is plotted versus the logarithm of the average flux for each of the knots. Epoch 1 (black circles), epoch 2 (red triangles), epoch 3 (green squares), and epoch 4 (blue stars). Variability is detected whenever the maximum deviation between epochs is greater than 3σ, where σ is the standard deviation of the sky background in the epoch 4 image. The dotted line shows 3σ from average.