Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
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.
Astronomy
Redshift Velocity Calculator
Compute the recession velocity of a distant galaxy from its redshift z and the Hubble constant H₀ using v = c·z ≈ H₀·d, valid for nearby galaxies. The Hubble-Lemaître law — the empirical relation that established the expanding universe.
Key differences
| Stellar Luminosity Calculator | Redshift Velocity Calculator | |
|---|---|---|
| Category | Astronomy | Astronomy |
| Inputs required | 2 | 2 |
| Result | Stellar Luminosity (L☉) | Recession Velocity (km/s) |
| What it does | 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. | Compute the recession velocity of a distant galaxy from its redshift z and the Hubble constant H₀ using v = c·z ≈ H₀·d, valid for nearby galaxies. The Hubble-Lemaître law — the empirical relation that established the expanding universe. |