| Jun 2018 Nov 2018 | Science operations begin |
| Mar 2018Aug 2018 | First light |
| Oct 2017Feb 2018 | Fibre positioner ready for commissioning |
| Oct 2017 | MOS fibres installation on Plate B |
| May 2017Feb 2018 | Spectrograph ready for commissioning |
| Apr 2017 | MOS fibres installation on Plate A |
| Apr 2017 | LIFU installation |
| Mar 2016 | Start of system integration |
| Jan 2016 | First component (handling trolley) arrives at the WHT | Apr 2015 | Most of system final design reviews completed |
| Mar 2015 | Conference: "Multi-Object Spectroscopy in the Next Decade: Big Questions, Large Surveys and Wide Fields" |
| Apr 2014 | Blank for prime-focus corrector lens 1 is ordered |
| Mar 2014 | Science CCDs are ordered |
| Feb 2014 | First MOS fibre prototype |
| Jan 2014 | Final spectrograph optical design |
| Dec 2013 | GAIA launch |
| Nov 2013 | Five of the six prime-focus corrector blanks are ordered |
| Jul 2013 | Final prime-focus optical design |
| Mar 2013 | Preliminary design completion |
| Oct 2012 | Workshop: "La Palma and Calar Alto Observatories, Science in the Next Decade" |
| Dec 2011 | Science case delivery |
| Sep 2011 | Kick-off meeting |
| Mar 2010 | Workshop: "Science with the William Herschel Telescope 2010-2020" |
| Sep 2008 | Report by the European Telescope Strategic Review Committee of ASTRONET on "Europe's 2-4m Telescopes Over the Decade to 2020" |