[eric-hu]

Probably direct from the sun. There's an what-if about using moonlight to start a fire

https://what-if.xkcd.com/145/

> First, here's a general rule of thumb: You can't use lenses and mirrors to make something hotter than the surface of the light source itself. In other words, you can't use sunlight to make something hotter than the surface of the Sun.

...

> The Sun is about 5,000°C, so our rule says you can't focus sunlight with lenses and mirrors to get something any hotter than 5,000°C. The Moon's sunlit surface is a little over 100°C, so you can't focus moonlight to make something hotter than about 100°C.

The cloud tops of Jupiter are estimated to be -280 degrees F.

[ggm]

Yes, my basis for wondering was reflectance to surface area providing more PV energy than capture by the same PV surface from a higher energy point source. About all I've got is less directional, so at lower intensity more available for less tracking effort.