Measuring the line spectra of inert gases and metal vapors using a grating spectrometer

In the experiment P5.7.2.1, the grating spectrometer is used to observe the spectral lines of inert gases and metal vapors which have been excited to luminance. To identify the initially “unknown” spectral lines, the angles of deviation are measured and then converted to the corresponding wavelength.
The resolution of the grating spectrometer is sufficient to determine the distance between the two yellow sodium D-lines λ(D₁) – λ(D₂) = 0,60 nm with an accuracy of 0.10 nm. However, this high resolution is achieved at the cost of a loss of intensity, as a significant part of the radiation is lost in the undiffracted zero order and the rest is distributed over multiple diffraction orders on both sides of the zero order.