Giant Mirror Odyssey

1993/11/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Materialak

A giant mirror weighing 45 tons has been built at the German factory in Mainz, Schott. Despite the 8.6 meters in diameter, this monolithic glass disc only has a thickness of 17.7 centimeters. They had to turn this album around to work their two faces, one concave and another convex. This mirror is one of the four mirrors of the “Veri Large Telescope” or VLT of the observatory that Europe is building on Cerro Paranal in Chile.

The mirror has been moulded into a single piece at a temperature of 1600°C, an hour later it was centrifuged. The glass has been cooled for four months under a hood to room temperature and subsequently machined. In addition, a heat treatment has been applied for another eight months to turn it into glass ceramics. Thus, the mirror has great stability. For example, the thermal expansion coefficient is zero.

This gigantic mirror begins its journey aboard a special boat to descend the Rhine River. After passing the Channel of La Mancha, you will be taken to the REOSC society in the Paris area, where you will leave the two sides of the mirror polished. After crossing the Atlantic Ocean to America and passing through the Panama Canal to the Pacific, you will arrive in the Chilean city of Antofagasta. At 2,664 meters of altitude it will take you dry to Cerro Paranal.

Thanks to the VTL telescope you can see from its observatory the galaxies farthest from the universe, which are ten billion light years and perhaps farther away.