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Calcimator

Redshift Calculator

Calculate cosmological redshift, recessional velocity, distance, and lookback time using Hubble's law.

Inputs

nm
nm
km/s

Results

Redshift (z)

0

Velocity from Redshift

0 km/s

Distance

142.86 Mpc

Lookback Time

0.14 billion years

Relativistic Redshift0.033932
Distance0.14 Gly
How to Use This Calculator
  1. Enter the Observed Wavelength (nm) of the spectral line measured in the spectrum of the galaxy or quasar.
  2. Enter the Rest Wavelength (nm) β€” the lab-frame wavelength of the same line; H-alpha is 656.3 nm.
  3. The Redshift (z) is computed automatically from (Ξ»_obs βˆ’ Ξ»_rest) / Ξ»_rest.
  4. Alternatively, enter a Recessional Velocity (km/s) to compute the corresponding redshift from velocity.
  5. Read Distance (Mpc and Gly) and Lookback Time (billion years) to place the object in cosmic context.
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Formula

z = (Ξ»_obs - Ξ»_rest) / Ξ»_rest

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