CIW: Carnegie Commits to Giant Magellan Telescope

[bystander]

Carnegie Commits to Giant Magellan Telescope Construction
Carnegie Institution for Science, Washington, DC - 12 May 2010

At its annual May meeting, the Carnegie Institution for Science board of trustees enthusiastically endorsed the construction of the proposed Giant Magellan Telescope (GMT). The GMT will be the first in the next generation of astronomical observatories that will drive new scientific discoveries. ...

The GMT will be built at Carnegie’s Las Campanas Observatory in Chile, and will be operated by a consortium of institutions from the United States, South Korea, and Australia. Larger and more powerful than any previous optical telescope, it will have ten times the light-gathering power of current ground-based telescopes, and will produce images 10 times sharper than those from the Hubble Space Telescope. The GMT will use the latest in Adaptive Optics technology to remove blurring caused by the Earth’s atmosphere to produce images with unprecedented sensitivity and clarity.
...
The novel design of the GMT will combine seven 8.4-meter primary mirror segments resulting in an equivalent 24.5-meter telescope. The first so-called off axis mirror, under development at the Steward Observatory Mirror Lab at the University of Arizona, will be completed by the end of the year.

The GMT is poised to address some of the most fundamental and outstanding questions in astronomy: the nature of the mysterious dark matter and dark energy, the origin of the first stars and first galaxies, and how stars, galaxies and black holes evolve over time. One of the particular strengths of the GMT will be its ability to image planets around nearby stars and to search for signs of life in their atmospheres.

[neufer]

<<The Gregorian telescope is a type of reflecting telescope designed by Scottish mathematician and astronomer, James Gregory in the 17th century and first built in 1673 by Robert Hooke. The design pre-dates the first practical reflecting telescope, the Newtonian telescope built by Sir Isaac Newton in 1668, and was not successfully built until 5 years after Newton's first reflecting telescope.

Examples of Gregorian telescopes:

• * The Green Bank Telescope, the Arecibo Observatory, and the Allen Telescope Array
  _____ are all radio telescopes employing off-axis Gregorian optics.
  * The Vatican Advanced Technology Telescope and the Magellan telescopes use Gregorian optics.
  * The Large Binocular Telescope and the Giant Magellan Telescope will use Gregorian optics.

The Gregorian telescope is named after the James Gregory design which appeared in his 1663 publication Optica Promota (The Advance of Optics). Similar theoretical designs have been found in the writings of Bonaventura Cavalieri and Marin Mersenne. Gregory's early attempts to build the telescope failed, since he had no practical skill himself and he could find no optician capable of actually constructing one. It was not until ten years after Gregory's publication, aided by the interest of experimental scientist Robert Hooke, that a working instrument was created.

The Gregorian telescope consists of two concave mirrors; the primary mirror (a concave paraboloid) collects the light and brings it to a focus before the secondary mirror (a concave ellipsoid) where it is reflected back through a hole in the centre of the primary, and thence out the bottom end of the instrument where it can be viewed with the aid of the eyepiece.



The Gregorian design solved the problem of viewing the image in a reflector by allowing the observer to stand behind the primary mirror. This design of telescope renders an upright image, making it useful for terrestrial observations. It also works as a telephoto in that the tube is much shorter than the system's actual focal length.

The design was largely superseded by the Cassegrain telescope. It is still used for some spotting scopes because this design creates an erect image without the need for prisms. The Steward Observatory Mirror Lab has been making mirrors for large Gregorian telescopes at least since 1985.

In the Gregorian design, the primary mirror creates an actual image before the secondary mirror. This allows for a field stop to be placed at this location, so that the light from outside the field of view does not reach the secondary mirror. This is a major advantage for solar telescopes, where a field stop (Gregorian stop) can reduce the amount of heat reaching the secondary mirror and subsequent optical components. The Solar Optical Telescope on the Hinode satellite is one example of this design.

For amateur telescope makers the Gregorian can be less difficult to fabricate than a Cassegrain because the concave secondary is Foucault testable like the primary, which is not the case with the Cassegrain's convex secondary.>>

[bystander]

UChicago commits $50 million toward building Giant Magellan Telescope
University of Chicago | 19 July 2010

The University of Chicago has joined the effort to build the world’s largest telescope in Chile, which will eclipse the image quality even of the Hubble Space Telescope, as the quest continues for answers to some the deepest mysteries of modern cosmology.

The University will provide $50 million to become a founding partner in the project called the Giant Magellan Telescope, which will be able to produce images of objects 100 times fainter than the Hubble Space Telescope can detect.

The University of Chicago Joins the Giant Magellan Telescope Project
Giant Magellan Telescope Organization (GMTO) | 19 July 2010

The Giant Magellan Telescope Organization (GMTO) Corporation is pleased to announce that the University of Chicago has joined the partnership that will construct the 25-meter Giant Magellan Telescope (GMT), a state of the art astronomical observatory. The GMT will be used to address fundamental questions in cosmology and astrophysics and to explore worlds around other stars.

The University of Chicago joins an international consortium of leading educational and research institutions from the United States, South Korea, and Australia to build and operate the GMT. The addition of Chicago raises the number of GMT founding institutions to ten. Together with recent major financial commitments to construction from the Korea Astronomy and Space Science Institute, the Australian National University, the Carnegie Institution for Science, and other founding partners, Chicago’s participation brings the partnership closer to the funding level needed to begin construction, just over $240M or approximately 35% of the total project cost.

GMT will be located at one of the world’s premier astronomical observing sites, the Las Campanas Observatory in the Chilean Andes. It will be one of the world’s largest and most powerful astronomical observatories and will have more light gathering power than all of the current telescopes in Chile combined. The GMT will use the latest techniques in Adaptive Optics to remove blurring caused by the Earth’s atmosphere, producing visible and infrared images that are up to ten times sharper than those from the Hubble Space Telescope. The unprecedented clarity and sensitivity of these images will provide astronomers with a powerful new tool to study still-unsolved mysteries of the universe, including the formation of planetary systems, the growth of black holes, and the nature of dark matter and dark energy.

The GMT features an innovative design of seven 8.4 meter, or 27 foot, diameter primary mirrors arranged in a hexagon. The seven mirrors, six of which are off-axis, will work in concert to produce a single telescope 25 meters or 82 feet in diameter. The mirrors are being developed at the Steward Observatory Mirror Laboratory (SOML) at the University of Arizona. The first off-axis mirror is in the final stages of polishing and will be completed by the end of the year. In addition, the GMTO is laying the groundwork to cast the second mirror blank in the summer of 2011.