ESPRESSO Instrument Achieves First Light with All Four Unit Telescopes (image) ESO Share Print E-Mail Caption The ESPRESSO instrument on ESO's Very Large Telescope in Chile has used the combined light of all four of the 8.2-meter Unit Telescopes for the first time. Combining light from the Unit Telescopes in this way makes the VLT the largest optical telescope in existence in terms of collecting area. This picture shows in highly simplified form how the light collected by all four VLT Unit Telescopes is combined in the ESPRESSO instrument, located under the VLT platform. Credit ESO/L. Calçada Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.