To create high resolution spectra we can attach the LHIRES III from Shelyak Instruments that was sponsored by the NTU Alumni fund. This spectrograph uses a 2400 grating per mm reflective grating as well as a 15-35 micrometer wide slit. This results in an approximate resolution of 0.035 nm at 656 nm.
The Littrow design means the collimating lens is used to collimate the input light as well as create an image of the spectrum. A neon light source is integrated and used as a reference source. The entire spectrum is so large that the appropriate section to be imaged has to be tuned using a micrometer screw.