This instrument has very good optic and mechanical features which allow the exact measurement of the optical rays deviation angles. Therefore it can determine the refractive index of solids and liquids and the wavelength of monochromatic sources.
Base: made of fire-varnished cast-iron Ø 17.5 cm and divided in 360° with a precision of 1°. It has two diametrically opposite vernier scales which enable a valuation of 1/10°.
Telescope: it has achromatic objectives with an 178 mm focal length and an eyepiece 15x. Focusing allows fine regulation. Collimator: endowed with achromatic objective with 178mm focal length and with a steady adjustable slit up to 6mm. The plane of the prism can be adjusted both vertically and horizontally and is supplied with boss-heads for the fixing of the diffraction grating.
- 1 Crown glass equilateral prism 32 x 32mm.
- 1 diffraction grating 500 lines/mm.
- 1 magnifying.