| The Twin Quasar Q0957+561 | |
|---|---|
 The Twin Quasar QSO 0957+561, which lies 8.7 billion light-years from Earth, is seen right in the center of this picture.[1] | |
| Observation data (Epoch J2000) | |
| Constellation | Ursa Major |
| Right ascension | 10h 01m 20.99s |
| Declination | +55° 53′ 56.5″ |
| Redshift | 1.413 |
| Distance | 8,700,000,000 ly (2,400,000,000 pc) |
| Type | Rad |
| Apparent dimensions (V) | 6" distance |
| Apparent magnitude (V) | 16.7 |
| Other designations | |
| Twin Quasar, Double Quasar, Twin QSO, QSO 0957+561, Q0957+561, SBS 0957+561, TXS 0957+561, 8C 0958+561, PGC 2518326, A: USNO-A2 1425-7427021 B:USNO-A2 1425-7427023 | |
| See also: Quasar, List of quasars | |
The Twin Quasar (also known as Twin QSO, Double Quasar, SBS 0957+561, TXS 0957+561, Q0957+561 or QSO 0957+561 A/B), was discovered in 1979 and was the first identified gravitationally lensed object,[citation needed] not to be confused with the first detection of light deflection in 1919. It is a quasar that appears as two images, a result from gravitational lensing caused by the galaxy YGKOW G1 that is located directly between Earth and the quasar.
- ^ "Seeing double". ESA/Hubble Picture of the Week. Retrieved 20 January 2014.