The term "skyshine" is used to designate the sun's rays that are reflected from the sky and clouds in contradistinction to the rays received directly from the sun itself. An object placed on the sunny side of a street receives not only rays from the sun, but also the reflected rays from the sky. If an object is placed on the shady side of the street, only the rays reflected from the sky (skyshine) are received. If the object is again placed on the sunny side of the street and if a long cylinder pointed directly at the sun is placed over the object, the rays from the sky are cut off by the walls of the cylinder, and only the rays directly from the sun pass along the inside of the cylinder to the object at the bottom.
No studies on the antirachitic effect of skyshine have been recorded.
TISDALL FF, BROWN A. ANTIRACHITIC EFFECT OF SKYSHINE. Am J Dis Child. 1927;34(5):737-741. doi:10.1001/archpedi.1927.04130230021003