Spectroscope

The precision mechanical rotary platform on this spectroscope goes back to the time that angular measurements were made around an equilateral prism to determine the precise angles of each wavelength of light from a light source. These angles were compared with known wavelengths emitted from spectral lamps to determine their exact wavelengths.

The rotary platform has a vernier, and a telescope that is focused on and adjustable slit through a collimator lens. When the equilateral prism is inserted in the middle, it bends the beam from the slit, and breaks it into different wavelengths. A cross hair on the telescope is lined up with each color of light to measure its wavelength based on the reading on the vernier scale. The resolution is usually in the order of arc minutes.