The sixth 8.4-meter mirror is about two stories tall and was made in Richard F.'s mirror laboratory.
"The most important part of a telescope islight collecting mirror. The larger the mirror, the deeper we can look into the Universe and the more details we can observe. The unique design of the main mirror consists of seven of the largest mirrors in the world. Casting the sixth mirror is an important step toward completing the telescope. Once launched, the Giant Magellan Telescope will produce images ten times clearer than the Hubble Space Telescope. The discoveries these mirrors will make will change our understanding of the universe."
James Fanson, Project Manager, Giant Magellan Telescope
The process of casting a giant mirror in the laboratoryRichard F. Caris in Arizona involved melting nearly 20 tons of high-purity, low-expansion borosilicate glass (called E6 glass) in the world's only spinning furnace designed to cast giant telescope mirrors. At the peak of the melting process, the furnace rotates at five revolutions per minute, heating the glass to 1165°C for about five hours until the liquid takes the desired shape.
A peak temperature event is called a "strongfire ”and occurred on March 6, 2021. The mirror then goes into a firing process for a month, during which the glass is cooled and the kiln rotates at a slower speed to relieve internal stress and harden the glass. The mirror will cool down to room temperature for another 1.5 months. This "centrifugal casting" process gives the mirror surface a special parabolic shape after cooling.
The first two giant mirrors are finished andstored in Tucson, Arizona, the sixth mirror will soon join three others at different stages of production in the mirror laboratory. The polishing of the front surface of the third mirror reached an accuracy of 70 nanometers, and less than a year has passed since the completion of the work. For the fourth mirror, the back surface was polished and load distributors were attached to it so that the mirror could be manipulated during operation. The fifth mirror was cast in November 2017, and the seventh mirror is expected to be cast in 2023. In addition, it is planned to make an eighth spare mirror, which can be used to replace another broken or serviceable mirror.
In the late 2020s, giant mirrors will betransported over a distance of more than 8,100 kilometers to the future home of the giant Magellan Telescope in the Chilean Atacama Desert at the Las Campanas Observatory at an altitude of more than 2,500 meters above sea level. The site is known as one of the best astronomical sites on the planet, with clear skies, low light pollution and stable airflow producing exceptionally clear images.
When will the Giant Magellan Telescope be available?fully operational, its array of seven mirrors will have a total aperture ratio of 368 m² - enough to see the torch engraved on a coin from a distance of almost 160 kilometers. This viewing capacity is ten times greater than that of the famous Hubble Space Telescope, and four times greater than that of the long-awaited James Webb Space Telescope, expected to launch in late 2021.
"This unprecedented combination of aperture ratio,The efficiency and resolution of the image will allow us to make new discoveries in all areas of astronomy, especially in areas that require the highest spatial and spectral resolution, such as the search for other exoplanets. We will have unique capabilities to study planets at high resolution, which is key to understanding whether a planet has a rocky composition like our Earth, whether it contains liquid water, and whether its atmosphere contains the right combination of molecules to signal the presence of life." .
Rebecca Bernstein, chief scientist at the Giant Magellan Telescope
Mirrors are also an important part of opticaldesign that allows for the use of the Giant Magellanic Telescope, and it also has the widest field of view of any ultra-large telescope (ELT) in the 30-meter class. The unique optical design will make the Magellan Giant Telescope the most optically efficient ELT. Each photon of light collected by mirrors requires only two reflections to direct the light onto wide-angle fixtures, and only three reflections to provide light for instruments that use a small field of view and the highest possible spatial resolution.
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