The first observation of this phenomenon was dubbed the "Twin Quasar."
The Xallarap effect is an alteration in the observation of this phenomenon caused by the motion of the source. The MOA experiment is studying this phenomenon in relation to dark matter. The galaxy cluster Abell 2218 is one of the most notable sources of this phenomenon, which is used by the PLANET network to detect extrasolar planets. The first observation of this phenomenon was dubbed the "Twin Quasar." An Einstein Cross can be created by this phenomenon, while the Einstein Ring occurs when the observer, the source of the light, and an extremely massive object are all along a straight line. FTP, name this relativistic effect in which a very massive object such as a galaxy bends light around itself like a certain optical device.
The Xallarap effect is an alteration in the observation of this phenomenon caused by the motion of the source.
{Gravitational Lensing}