A light returning target for a photometer. The light returning target
comprises a ball lens, and a cradle. The cradle has a hemispherical
receptacle in which the lens is intimately received. Preferably, the lens
is formed of fused silica, the receptacle is polished sufficiently to
reflect, more than it scatters, light, and at least the surface of the
receptacle is formed of a material that absorbs, more than it reflects,
light.