The ELT will gather 100,000,000 times more light than the human eye, 8,000,000 times more than Galileo’s telescope, and 26 times more than a single VLT Unit Telescope. In fact, the ELT will gather more light than all of the existing 8–10-metre class telescopes on the planet, combined.
via Is the Extremely Large Telescope big enough to find alien life?.