Giant mirror for the VLT telescope

1991/05/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Astronautika

To produce VTL or Very Large Telescope, 45 tons of molten glass prepare a mirror of 8 meters in diameter. This telescope is intended to be installed on Cerro Paraná in Chile, in the Atacama Desert. With four 8-metre mirrors, astronomers want to explore the Universe up to a distance of 10,000 million light years.

Everything depends on the manufacture of the mirror. With classical technology, the mirror stiffens the thickness, but in this way the mirror would weigh 150 tons. To make a finer mirror 200 hydraulic cylinders will be placed to compensate for each deformation. Because the thin mirror is very fragile.

The house manufacturer, Schott, hopes that one of the two mirrors will be broken, but in the first one it has triumphed. 45 tons of centrifuged glass have filled the concave mold. Now only the glass needs to cool. It is a job of about four months.