The Gran Telescopio Canarias, or GTC, or GRANTECAN, is the biggest telescope at the observatory on La Palma. Video journalist Brady Haran has a look inside.
With extra commentary by proper astronomer Professor Mike Merrifield, from the University of Nottingham.
GTC website (English): http://www.gtc.iac.es/en/pages/gtc.php?lang=EN
IAC website: http://www.iac.es/
Deep Sky Videos website: http://www.deepskyvideos.com/