Track background sky level in Image History

I would find it very useful if the Image History tool would also track background sky brightness in addition to HFR and star count.

Our local imaging conditions vary quite a lot especially during the winter depending on if there is snow on the ground, haze in the air (esp. in very cold weather), and so on. It would be very handy to see the background level of the subs in the graph to quickly get a hunch of the current imaging conditions.