Cygnus A

Cygnus A (i.e., 3C 405 or QSO B1957+405) is a radio galaxy, one of the first identified. As a radio source, it was discovered by Grote Reber in 1938, with his back-yard radio telescope, the first radio receiver built for that purpose. An apparent quasar was discovered within it in the 1990s: this is no mystery since quasars are interpreted as active galactic nuclei (AGNs), which are also often the driver for strong radio emission from galaxies. Cygnus A demonstrates the involvement of jets in creating a radio galaxy's radio emission; its strongest radio signal comes from two regions in opposite directions from the galaxy itself.