For the full story see the NASA Hubble site: NASA/ESA managed to combine the powerful Hubble Space Telescope with the incredible sling-shot magnification of gravitational lensing to produce what appears to be mankind’s first visible-light image of an accretion disk. .
An international team of astronomers has used a new technique to study the bright disc of matter surrounding a faraway black hole. Using the NASA/ESA Hubble Space Telescope, combined with the gravitational lensing effect of stars in a distant galaxy , the team measured the disc’s size and studied the colours (and hence the temperatures) of different parts of the disc. These observations show a level of precision equivalent to spotting individual grains of sand on the surface of the Moon.