Similar to the linear offset image, above, except typically shifted towards the blue. Stretch, color mapping, etc, are the same. Like the linear fit slopes, these are roughly 25, but shifted generally higher due to the overall curvature, which is downward. Information is the same as for the linear slope histogram above. As for the linear fits, slope images are spatially fairly smooth.
Details are as described above for the linear slope image.
Typical value is around -0.001, but there is often considerable variation. Spots, probably due to the recent passage of bright stars, can be seen in some of these images. It can happen that some pixels are unreasonably high in this histogram. A bad example is given by the north H camera on 970608n. It is proposed to set the thresholds for such pixels to the median threshold as previously determined.