Direct-vision prism

Light passes directly through the prism as shown..A single bright specrtrum is formed.

The prism is a combination of three individual prisms. The two end pieces have a refractive index of 1.5. The middle section has a refractive index of ~1.76 (data to be confirmed).

The actual size is 3.5 x 1.4 x 1.4 cm.

To photograph a spectrum the prism is mounted in black card and placed directly in front of a digital camera with a small objective lens.