This grating was made for Jerrell-Ash by Bausch & Lomb. 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 - 295
Blazed at 210nm
Catalog number 985-30-40-36
Coating - Al (?)

Most of the grating is in extremely fine condition, however there are some large coating blemishes in one corner of the grating and some smaller ones along the top margin. A 10mm wide mask would suffice to completely cover the extent of the coating flaws leaving most of the grating in a near-unblemished state.

Photo set 1651