Constant Deviation Wavelength Spectrometer is a direct instrument for various visible wavelengths of visible spectrum, used in various departments for the study of spectral series, emission spectra of elements, absorption spectra of compounds, fluorescence spectra, band spectra, zeeman effect & determination of e/m detection of traces of metallic elements. The Raman spectra of liquids, polarization studies in Raman spectra, rapid qualitative analysis of metallic constituents of unknown substances, detection of rate-earth in minerals, quantative spectrum analysis used as monochromator, consists ofHeavy stable base having a pillar on which mounted a platform collimator / telescope prism housing.Carrying prism pillion and broca type refractive index 1. 65/1. 74 housed properly with a cover rotatable by wavelength drum, outside.