A set of nine 35mm format diffraction gratings slides, mounted in 50mm carriers. Six of them have multiple slits approximately 0.0625mm wide, numbered from 1 to 6. The separations between slit centres is 0.25mm. The remaining three slides are coarse gratings numbered 1 to 3 with variations as follows: 150 slits with the same width and separation as the multiple slit slides, 150 slits, half the width but with the same separation, 300 slits, half the width and half the separation.
.jpg)