The 77250B-FH from Newport Corporation is a Hand Operated Monochromator that operates from 0.2 to 23 μm using Newport’s interchangeable diffraction gratings. It has a focal length of 125 mm and an aperture ratio of F/3.7. This monochromator is based on an Ebert-Fastie design that can be operated by hand and has a wavelength accuracy of 1 nm with a step resolution of 0.1 nm. It consists of a fixed slit assembly with Newport’s 77294 slit holders at the I/O ports that can hold fixed slits ranging from 50 µm to 6.32 mm in width. The monochromator has an optical axis height that can be adjusted using Newport’s 77387 mounting kits to match the source/detector.