HDRi Sky Map Altitude are complete 360 degree x 180 degree panoramas in .exr and .hdr format for use as a spherical environment in 3D scenes. Note 15.000 (km) refers to altitude and 15 (degrees) the Sun angle, where 0 means the sun is on the horizon and 90 means directly overhead.
The resolution is 7500px wide, good enough in most cases to be used as the directly visible sky. When you want more control, or the sky is visibly low res, you can use the supplied maps in the folder Bonus.
Full Dynamic Range Sky Map:
Does not need lights in the 3D scene, is the map that gives light and shadows.