Formula:
`f`obs = `f`emit * √((1 - `v`/`c`) / (1 + `v`/`c`))
Where:
- `f`obs: Observed frequency (Hz)
- `f`emit: Emitted (rest) frequency (Hz)
- `v`: Relative velocity of recession (m/s)
- `c`: Speed of light in vacuum (~299,792,458 m/s)
`f`obs = `f`emit * √((1 - `v`/`c`) / (1 + `v`/`c`))
Where: