If you want easy non security just answer the last word of the question.

This is actually quite good. OC? / Source?

Kaas

This covers much of it. Also inderect sunlight matters too. So any percentage non sky (groud/horizon) the panel “sees” wil have less indirect sunlight than the (blue or even cloudy) sky going towards the panel.

So like pizza essentially.

This picture seems to be from Animorphs by Applegate. Those where good old times. What a crazy book series.

Cologne ≠ colon