MoonBlueGreySunW.hdr = white sun
MoonBlueGreySunY.hdr = yellowish sun (R/G/B 255/255/235)

The lower the "sun" is (Bryce IBL Y < 90), the bluer
the ambient light gets. This is also so for the yellow
sun.

The light probes in Bryce IBL are identified by a large
"W" (white) or "Y" (yellow) because the colour hue cannot
be seen in the thumbnail.
