Spectral Line Redshift

How to use this tool

1. Calculate redshift and radial velocity using both small-shift and relativistic formulas.
2. Set rest wavelength, observed wavelength in the indicated units.
3. Calculate and compare redshift, low-redshift velocity, special-relativistic velocity.

Try this example

{
  "rest": 500,
  "observed": 550
}

Accuracy and scope

Doppler-only velocity model. Cosmological redshift cannot generally be interpreted as this local velocity.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.