A bidirectional reflectance accessory for spectroscopic measurements

A dual beam bidirectional reflectance attachment, which permits the sample plane to be tilted to plus or minus 45 degrees , is described. No restriction is placed on the type of sample which can be investigated because the incident light impinges on the sample from above. Reflectance spectra of a variety of materials are shown, as well as an indicatrix for a specular and a diffuse reflector. The use of this attachment provides spectra of the kind necessary for interpreting terrestrial and planetary remote sensing data.