comparison spectrum

comparison spectrum

The spectrum of one or more known substances under terrestrial conditions that is used in astronomy as a standard of comparison for investigating spectra of celestial objects; it provides, for example, a zero Doppler shift.

comparison spectrum

[kəm′par·ə·sən ‚spek·trəm] (spectroscopy) A line spectrum whose wavelengths are accurately known, and which is matched with another spectrum to determine the wavelengths of the latter.