The answer to this question is pretty simple : Go outside.
How many suns do you see in the sky?

What is the sun??? => The sun is ONE infinite light.

So to render with IDL and GC?? (as you should always do)

Load BB's free sphere, load a good texture on it of about 10.000 wide to 5.000 pixels high, and put ONE infinite light at the suns position and set it  between 65 and 75% intensity.

That is the ONLY valuable light set for outdoor renders.
And you have control of the IDL with the HSV node on BB's sphere.

And that did not take me a week to figure out.

=> There is NO second sun in the sky.
=> And NO there is no image on the sun either. ( IBL is OLD fake. Forget it. )

Happy Posering,
Tony

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!