Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Astronomy
Planetary Transit Calculator
Estimate when inner planets Mercury and Venus will cross the disk of the Sun as seen from a specific location on Earth. Used by astronomers and educators to plan observations of these rare celestial events.
Fill in the required fields to see your result.
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.
Key differences
| Planetary Transit Calculator | Redshift Velocity Calculator | |
|---|---|---|
| Category | Astronomy | Astronomy |
| Inputs required | 2 | 1 |
| Result | Next Transit in (days) | Recession Velocity (km/s) |
| What it does | Estimate when inner planets Mercury and Venus will cross the disk of the Sun as seen from a specific location on Earth. Used by astronomers and educators to plan observations of these rare celestial events. | 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. |