SDSS J114816.64+525150.3 (J1148+5251) was the most distant known quasar when it was discovered in 2003, at redshift Z=6.419.

[2] The quasar is powered by a 3x109 solar mass supermassive black hole.

[3] The Virtual Telescope Project imaged the quasar between March and April 2024, with a 350-millimeter (14 in) Celestron Schmidt–Cassegrain telescope, on a Software Bisque Paramount ME robotic mount.

A total of 81, 300-second exposures were combined, for a total of almost 7 hours of exposure, recording sources as faint as about magnitude R=25.

The team termed it "the most distant quasar observable at visible wavelengths".