UK researchers have signed the contract that will lead to the development of one of the first instruments for the European Extremely Large Telescope, BBC News reports.

The E-ELT will be the biggest optical and infrared observatory ever constructed, with a primary mirror just short of 40m across.

A British-led consortium will make an around $76,5 million-worth spectrograph called Harmoni.

This will tease apart the colors of distant galaxies to determine the properties of those objects.

Its data will help astronomers understand their composition, the physics at work, and their dynamics - how the galaxies move through space.

The deal will see Oxford University lead the project, with Prof Niranjan Thatte at the helm, while assembly of the instrument will take place at the UK Astronomy Technology Centre in Edinburgh.

Harmoni's consortium draws on the talents of companies and institutions across Europe, with major contributions from France and Spain.

Tim de Zeeuw, ESO's director general, said the contracts now being signed by his organisation kept the telescope on schedule to gather "first light" in late 2024.

"Last week, we signed the German-led camera, Micado. And the (Dutch-led) mid-infrared instrument, Metis, which is also paid out of construction funds - we will sign that next Monday.

"Then in February, we hope to award the contract for the dome and the support structure for the mirror," he told BBC News.

The telescope will be placed atop Cerro Armazones, a mountain in Chile's Atacama Desert.