Uploaded February 2026 | Updated September 2026, 2 weeks ago

---

How does the light captured by ESO's Extremely Large Telescope reach the instruments that will analyse it scientifically? That's the job of the pre-focal stations, which will no only deliver the light to the instruments, but also keep the telescope optics in check.

Discover more about ESO’s ELT at: elt.eso.org

Watch our ELT playlist here: youtube.com/watch?v=6lSTmjqkLoI&list=PLSZ2Jv0bEZHy7el0mIrOMRKkhCw8pemaZ&index=1

Credit:
ESO
Directed by: Angelos Tsaousis
Editing: Angelos Tsaousis
Written by: Bárbara Ferreira
Music: Jon Kennedy – Boom Clack (Martin Brew Remix).
Footage and photos: ESO, A. Tsaousis, L. Calçada, M. Kornmesser, J. Porte, F. Carrasco.
Web and technical support: R.Shida.
Acknowledgements: IDOM

More information and download options: eso.org/public/videos/eltu_PFS