This is a certified precision Bausch & Lomb optical grating. Much of the following information was taken from the nomenclature label fixed to the back of the grating substrate.

Grating size - 60 x 60 mm
Focal length - infinity
Grooves / mm - 1180
Blazed at 600nm
Catalog number 985-30-20-24
Coating - Al (?)

This grating has a significantly mottled aluminum coating as well as numerous scratches in the surface. It is suitable only for experimental purposes but still produces a nice spectrum.

Photo set 1655