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Blueshift
Blueshift is the decrease in the observed wavelength (and increase in frequency) of electromagnetic radiation from a source moving toward the observer. The spectrum shifts toward the blue (higher-frequency) end.
Doppler effect
The Doppler effect is the change in the observed frequency of a wave when there is relative motion between the source and the observer
Redshift
Redshift is the increase in the observed wavelength (and decrease in frequency) of electromagnetic radiation from a source moving away from the observer. The spectrum shifts toward the red (lower-frequency) end.