The sun tool

The sun tool is a very handy tool to control the lighting of the scene. Illustrated below is the location of the sun tool in the toolbar and what gets displayed when raised:

As for cameras, sun positions are listed in the current scene and saved by it. A sun position can be recalled from the current scene contents by double clicking it.

Sun positions are always relative to the position of the observer, so a sun position in the lower part of the tool means that it's night time. Always. Therefore, a sun position is only will be deterministic only for a fixed camera position. If the camera moves slightly, then the sun position will not be identical. Note that at a planetary scale, you won't notice the change unless you move by kilometers. But to be able to strictly reproduce a sun position, a camera position should be recorded too and both should be recalled.

Note that when the sun is moved in the sun tool, this freezes the simulation timeline as the sun position is overriden and doesn't move anymore with the planet orbit.