Astronomers captured the spectra of the two record breakers with a 3.5-metre (11.5 feet) telescope, located at the Apache Point Observatory in New Mexico, also the site of the SDSS telescope.

BBC: Most distant objects observed

Astronomers say that the key to SDSS's success in quasar spotting is its recording of precision digital data in five colours, which allows researchers to easily distinguish quasars from more common faint stars.

BBC: Most distant objects observed

In July, astronomers from the Sloan Digital Sky Survey (SDSS), which aims to map out a million galaxies, published a research paper in which they superimposed their own galaxy-clustering data on Wmap's microwave data.

BBC: NEWS | Science/Nature | Dark energy tops science class