markp (01/27/83)
I'm no expert, but I thought that the function of the slit was to give a "line" of light which is imaged by the grating to form the "lines" of a line-spectrum. Of course the narrower the slit the closer the lines of your spectrum can be without overlapping, but I'll bet that this is true only down to a certain slit narrowness beyond which the diffraction effect of the slit itself causes problems. Always ready to speculate, Mark R. Paulin ...decvax!teklabs!tekmdp!markp