Giant Magellan Telescope

Giant Magellan Telescope.

Using the aluminum layer as the mirror, because it is more durable and less expensive to maintain.

The glass didn't coat the aluminum layer yet.

Aluminum Staples

The pump sucks out the air from the chamber.

The electric current heats the filament melting the staples and removing any impurity of
aluminum.

Next, the second stronger electric current passing through the filament, and then aluminum
vaporizes the hot aluminum gas rises and condenses on the cold glass surface. 

The moisture and humidity are the enemy of the aluminum mirror, it needed to be maintained
every two years.

The mirror and mounting sttructure are the same materail, if the temperature changes and then
the mirror and mounting structure that would shrink or expand by the same amount.
So, you don't get distortion of the imagine.

During the procedure, the air jet blows debris away, it also cools the diamond tile which heated up by cut the metal.