Star
Hubble's Cepheid V1
The star that changed the size of the universe (1923)
The variable star Edwin Hubble found in Andromeda in 1923; its period–luminosity relation proved that the "Andromeda Nebula" is a separate galaxy outside the Milky Way. A Cepheid with a 31.4-day period; today the Hubble Space Telescope has observed it too.
| Type | Star |
|---|---|
| Constellation | Andromeda |
| Host galaxy | Andromeda (M31) |
| Distance | 765 kpc (M31) |
| Period | 31.4 days |
| Apparent magnitude | 18,5–19,5 |
| Type | Classical Cepheid |
| Discovery | October 1923, Hubble, 100-inch Hooker |
| Right ascension (J2000) | 0h 41m 27.3s |
| Declination (J2000) | +41° 10′ 11″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 49° S. North of latitude 49° N it never sets. It stands highest at midnight in September, the best time to observe it.