Hi, i am new here, so am not really sure wheather i am asking this qus at the right place. I have a Lab based qus. I just did the atomic spetra analysis using a diffraction grating, analysing hydrogen gas. But but when i calculate the wavelengths of the lines, its way off from the literature values. I asked my prof, he said somthing about the grating is actually for astronomy, and not really suited for this experiement. I have to find out wats the diffrence. so whats the diffrence between grating for astronomy and the normal gratings? I tried googling, cant really get any viable results. is there any refeance material I could look at?