Astrophysics (index)about

rest wavelength

(normal wavelength observed when not moving in relation to the source)

The rest wavelength of a source of electromagnetic radiation is the normal wavelength as observed when at rest in relation to the radiation source. When source and observer are relatively in motion, the wavelength observed is termed the observed wavelength.

Redshift is calculated as:

     difference in wavelength
z = ——————————————————————————
        rest wavelength

    observed wavelength - rest wavelength
z = —————————————————————————————————————
               rest wavelength


                  observed wavelength
rest wavelength = ———————————————————
                        1 + Z


Referenced by:
redshift (z)