Spectrometer direct reading – Spectroscope

The Spectroscope (Spectrometer direct reading) is used to observe and study linear emission and absorption spectrum. Equipped with an angle measuring scale, it is also used as a spectrometer to measure the angles and refractive index of prisms of various materials and to study the dependence of the index on the wavelength of monochromatic radiation.

It consists of a 360° protractor disc, graduated by 1°, adjusted to a fixed base. Two arms can rotate independently and lock around the disc, in position measured by a vernier.

One arm carries a telescope with objective achromatic lens and eyepiece system with focusing and reticle aiming. The other arm carries a viewfinder with a telescope-like objective lens and an adjustable 6mm slit. On the tray there is a bench for supporting a prism or diffraction barrier.

An additional system is a third tube, similar to the telescope and viewfinder, which also serves to project the scale of wavelengths of the visible spectrum at the level of the crosshair, so that it is visible to the observer at the same time as the observed spectrum.

Common filter lamps or spectral lamps such as the sodium lamp and Geissler tubes can be used as sources of light radiation. To make the spectrum lines visible in the eyepiece, the viewfinder is directed towards the observed light radiation and the optics are focused and adjusted.

The vernier reading of the telescope determines the position of the spectrum lines.

Technical Specifications

working wavelength: 400-800nm
objective focal length of collimator: 150mm
objective focal length of telescope: 150mm
eyepiece focal length of telescope: 25mm (low power)
eyepiece focal length of telescope: 12.5mm (high power)
objective focal length of drum
calibrated in wavelength: 100mm
minimum graduation of wavelength scale:
- 2mm per graduation for 400-500nm
- 5nm per graduation for 500-600nm
- 10nm per graduation for 600-700nm
- 20nm per graduation for 700-800nm
Prism: refracted edge angle of 60
side length not less than 32mm
error in measuring wavelength:
- not greater than 2nm for 400-500nm
- not greater than 5nm for 500-600nm
- not greater than 10nm for 600-700nm
- not greater than 20nm for 700-800nm