Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Astronomy
Redshift Velocity Calculator
Compute the recession velocity of a nearby galaxy from its redshift z using v = c·z, where c is the speed of light. Part of the Hubble-Lemaître law — the empirical relation that established the expanding universe.
Fill in the required fields to see your result.
Astronomy
Stellar Luminosity Calculator
Compute a star's luminosity in solar units (L☉) from its radius and surface temperature via the Stefan-Boltzmann law. The fundamental relationship between stellar size, temperature, and total energy output — and the basis of the Hertzsprung-Russell diagram.
Fill in the required fields to see your result.
Key differences
| Redshift Velocity Calculator | Stellar Luminosity Calculator | |
|---|---|---|
| Category | Astronomy | Astronomy |
| Inputs required | 1 | 2 |
| Result | Recession Velocity (km/s) | Stellar Luminosity (L☉) |
| What it does | Compute the recession velocity of a nearby galaxy from its redshift z using v = c·z, where c is the speed of light. Part of the Hubble-Lemaître law — the empirical relation that established the expanding universe. | Compute a star's luminosity in solar units (L☉) from its radius and surface temperature via the Stefan-Boltzmann law. The fundamental relationship between stellar size, temperature, and total energy output — and the basis of the Hertzsprung-Russell diagram. |