Previous -- Start Page -- Next (next picture is 636 kB in size)
The vacuum chamber for the annual re-aluminizing the 16-ton primary mirror of the Anglo-Australian Telescope. Once the air is removed down to 1 part in 100 million, aluminum is evaporated off electrically-heated tungstten filaments and afixes onto the previously cleaned mirror surface. The aluminum coating is just 1/10th of a micron thick and reflects 90% of the light.