The retardance of the retarder may be increased by varying the angle of incidence.Figure 16 shows the increase of retardance as a function of the incident angle.A good method for varying the angle is to mount the retarder in the special component carrier of the angular translator.By rotating the translator table,the angle of incidence can be accurately varied. *CAUTION:The surfaces of the polarizers and retarder are very easily scratched,and should be touched as little as possible.(The surfaces are cellulose acetate butyrate.) Glass Plate Size:50×50×6mm Refractive Index:1.518(at 588.9 nm) Acrylic Plate Size:50×50×19mm Refractive Index:1.48-1.50 Prism Angles::90°，450,450 Refractive Index:1.5 Material:BK-7Glass NOTE:the magnetic pads are strong enough to hold the prism with the steel base in a vertical position. Crossed-Arrow Target The crossed-arrow target is a useful object for object/image experiments.The fine lines on the horizontal arrow are a millimeter scale,which,when used in conjunction with the millimeter scale on the viewing screen,provides a convenient measure of magnification.The sharp edges and symmetrical shape are helpful for observing and analyzing spherical and chromatic aberration. Diffuser 1616 The retardance of the retarder may be increased by varying the angle of incidence. Figure 16 shows the increase of retardance as a function of the incident angle. A good method for varying the angle is to mount the retarder in the special component carrier of the angular translator. By rotating the translator table, the angle of incidence can be accurately varied. ★CAUTION: The surfaces of the polarizers and retarder are very easily scratched, and should be touched as little as possible. (The surfaces are cellulose acetate butyrate.) Glass Plate Size: 50 × 50 × 6 mm Refractive Index: 1.518 (at 588.9 nm) Acrylic Plate Size: 50 × 50 ×19 mm Refractive Index: 1.48 - 1 .50 Prism Angles: 900 , 450 , 450 Refractive Index: 1.5 Material: BK-7 Glass ★NOTE: the magnetic pads are strong enough to hold the prism with the steel base in a vertical position. Crossed-Arrow Target The crossed-arrow target is a useful object for object/image experiments. The fine lines on the horizontal arrow are a millimeter scale, which, when used in conjunction with the millimeter scale on the viewing screen, provides a convenient measure of magnification. The sharp edges and symmetrical shape are helpful for observing and analyzing spherical and chromatic aberration. Diffuser