European
Southern
Observatory

Telescope
Operations

The ELT will be part of ESO’s Paranal Observatory and will be operated from the same control room as other ESO telescopes such the Very Large Telescope.

In a nutshell

The ELT will be part of ESO’s Paranal Observatory and will be operated from the same control room as other ESO telescopes such the Very Large Telescope.

Once the enormous telescope and instruments of ESO’s ELT are up and running, scientific observations of the night sky can commence. A challenge for the observatory is to efficiently schedule a huge number of planned (and often unplanned, but opportune) observations of different phenomena across the night sky, and across a range of different science areas, whilst ensuring the highest possible quality for the resulting scientific data. This process has already been fine-tuned by ESO for the Very Large Telescope (VLT), and will be advanced for the ELT.  

The centre for the scientific observations will be 23km away from the ELT itself, in an operations building on Cerro Paranal, home of the VLT.  The control room here will be a hub of activity. From here, observing teams will control the ELT and its instruments, in the company of observing teams for the VLT telescopes, and powered by a gigantic array of computers. The work here will include continuous monitoring and optimisation of the telescope and instruments, pointing of the telescope to lock on to celestial objects, and subsequent evaluation of the scientific data (e.g., images and spectra). Essential support will also be provided by ESO engineers, who perform regular maintenance of the telescope.

Operations Model

ELT operations will be fully integrated within ESO’s Paranal operations following an evolved version of the current end-to-end science operations model. This will be based on the experience collected operating the present implementation of the model, on the integration of new ELT-specific requirements, and by considering technological advancements. As is the case for current ESO facilities, observing time will be assigned through competitive access. A mix of different observing modes and programme types will be offered to optimise efficiency and science return. The raw data and data products resulting from the ELT observations will be stored in the ESO science archive.

The ELT Technical Facility

Another important component of ESO’s ELT operations is the ELT Technical Facility at Paranal Observatory. This giant facility, built on a 6500-square-metre parcel of land, will serve as an assembly point for components of the ELT, as well as a place where they can be integrated and verified.  

Among the components are the 798 segment mirrors of the enormous primary mirror, which will be 39 metres in diameter. Before first light, the ELT Technical Facility will be used for storage, integration and coating of the M1 segments, as well as for the coating of the secondary and tertiary mirrors. Once the ELT starts operating, the facility will be the main hub for the maintenance of ELT’s optical components, including the recoating of M1 segments. Each day, two segments will be stripped of their old coating, washed and recoated, before being taken up the mountain (Cerro Armazones, where the ELT is located) for reinstallation on ESO’s ELT.