The series of techniques employed by astronomers to obtain distances to progressively more distant astronomical objects.
The Distance Ladder
| Object | Distance (pc) | Method |
|---|---|---|
| Sun, Solar System | 10-6 | Radar, Orbits |
| Alpha Centari | 1 | parallax |
| Hyades Cluster | 40 | Hipparcos parallax |
| Galaxy | 104 | Cepheids, Main Sequence Fitting |
| Andromeda | 105 | Cepheids, Supernovae, OB stars |
| Virgo Cluster | 107 | HST Cepheids, OB stars, SN |
| Beyond | 108 and up | Brightest Galaxies, Tully-Fisher |