If the alignment is not perfect, then multiple images are formed rather than a ring. HST images have been processed to separate the galaxy and quasar images . A gravitational lens is most effective if it is near midway between the observer and the distant object which is being lensed. The amplification, ratio of the lensed brightness of an object to its unlensed value, is larger if the line of sight passes very close to the lens. Several events of this type have been observed in the Large Magellanic Cloud, a small galaxy near our Milky Way.
Massive galaxies can also act as gravitational lenses.
Light from a source lying behind the galaxy is bent and focused to create an image or images of the source. Because the mass in a galaxy is not evenly distributed, the images are often deformed or magnified. Cluster gravitational lenses allow us to observe objects that are much too distant or too faint to be seen directly. And, since looking out to greater distances means looking farther back in time, we gain access to information about the early universe. Gravitational Lens Links APOD images of Gravitational Lenses.