The Giant Magellan Telescope is part of the next generation of telescopes - and while it's not ready to start looking at the stars, we do have a lot of information about the plans for this device. Here is everything you need to know about it.
When Will It Be Ready?
The Giant Magellan Telescope is expected to go online in 2025.
What Makes It Better Than Previous Telescopes?
The Giant Magellan Telescope, or GMT, has a new design that significantly increases its resolving power. The plan is to use six 27-foot mirrors slightly off-axis, surrounding a single on-axis monolith mirror of the same type. The result is a single useful surface about 80 feet across. It will begin with just four mirrors - the rest are coming later.
When you're trying to peer into the depths of space, bigger is always better. The GMT is expected to have a resolving power about ten times greater than the venerable Hubble Space Telescope.
How Exactly Do These Offset Mirrors Work?
When light reaches the telescope, it will bounce off of the primary mirror, then off of secondary mirrors, before it heads through the primary mirror in the center and reaches the imaging cameras. By precisely angling each of these mirrors, it's possible to eliminate distortion and create what is effectively a much larger lens than any single mirror would be capable of.
The primary mirrors are each carefully made at the Richard F. Caris Mirror Lab, which is
part of the University of Arizona. The lab creates the mirrors by forming a strong honeycomb structure to hold the outside reflective surface. The result is a larger, lighter mirror than can be made with conventional methods. As a secondary bonus, the mirrors can be cooled with fans to reduce heat distortion.
After making the mirrors, they're polished to exacting standards - about one-millionth of an inch. Diamond grinding wheels to more of the initial work, and they're followed by the use of non-Newtonian fluids to help create an aspheric surface. Frequent scans help to spot errors, with any variables taken into account for the next step of the polishing process.
As if that wasn't enough, the Giant Magellan Telescope will use hundreds of actuators under each of the secondary mirrors. These will help to adjust the mirrors when there's atmospheric turbulence and ensure each image is as clear as possible.
Where Is It Being Built?
The Giant Magellan Telescope is being built on Las Campanas Peak, which is located roughly in the middle of Chile's northern half. This peak is about 8500 feet above sea level, making it one of the highest and driest places in the world. The area has clear skies for about 300 nights every year, which is vital for maximizing the number of useful images a telescope can take.
There are other observatories in the area - notably including the other telescopes at the Las Campanas Observatory. Chile's mountains are one of the best locations in the world for telescopes, so the GMT is in excellent company.
What Else Should I Know About The Site?
The Giant Magellan Telescope receives numerous benefits from its chosen location. Aside from the excellent weather, the fact that it's being built at a developed site means that access from the road, electricity, water, and communication systems are already in place.
The location in the southern hemisphere is also helpful - many of the most exciting objects in the sky (including our galactic center and nearby galaxies) are easiest to see from that part of the world.
Light pollution is effectively nonexistent in the area. While the observatory can't control regional development, the location is available thanks to a long-term agreement with the government of Chile and the country is unlikely to allow development anywhere that could affect its operations.
How Big Will It Be?
Unless there's a surprise somewhere, the Giant Magellan Telescope will be the largest telescope on the planet. It's not going to hold that position forever - observatories are continually trying to make bigger and better telescopes - but there's no doubt that it's likely to have a significant impact on astronomy.
The area housing the telescope is even larger. The primary enclosure is set to be about 22 stories tall. Like most observatories, it can shut during the day to protect the telescope from problems like weather, sunlight, and dust. Meanwhile, built-in vents help improve airflow to equalize temperatures inside and outside the observatory once night falls.
Even more impressive is how mobile the telescope is. Being in a fixed position is terrible for telescopes, so the entire facility can spin over about three minutes to let the GMT point anywhere in the sky.
How Long Is The Giant Magellan Telescope Expected To Work For?
The telescope is expected to work for at least 50 years. The general lack of extreme weather conditions on the mountain makes it likely the telescope will work for the entirety of its planned life. However, defects in manufacturing - such as damage to one of its mirrors - could delay the start or useful life of the GMT.
Who Are The Stakeholders?
The Giant Magellan Telescope has four significant groups of Stakeholders. While individual members will change over time, we don't expect these categories to change.
The Governing Body consists of groups that are part of the GMTO Corporation, a nonprofit established in 2008 to manage the development, construction, and operation of the telescope. The founding members of the organization include a significant number of universities (with more expected to join), and the Founders' Agreement designates an overall Board of Directors.
The Partner Scientists include staff at various institutions who are nominated by a Scientific Advisory Committee. These scientists have a critical role for the observatory - helping decide where and when to aim the telescope as part of various studies. In many cases, the GMT will be used together with other telescopes to create a larger, better view of a specific area.
The User Community is less formal than the Partner Scientists, but they have a similar role. Time on telescopes isn't limited to high-ranking scientists. Indeed, many people can
schedule access to help the observatory complete its mission, and the high number of clear nights at its location help to ensure there are as many opportunities as possible for people to get involved.
Finally, the Observatory Staff will be maintained, operated, and managed by dedicated staff members. The observatory is expected to undergo regular improvements and expansions throughout its life, and staff on the ground are vital to these efforts.
What Kinds Of Instruments Will The Observatory Have?
The GMT will have several types of instruments, and we expect that more will come over time. Here are the systems and instruments currently set for addition.
Visible Echelle Spectrograph (G-CLEF)
The Visible Echelle Spectrograph is a general-purpose instrument designed to provide accurate readings for wavelengths of light. In the practical sense, this allows it to measure things like the exact velocities and atmospheres of exoplanets, the isotopes of stars, and the possible effects of dark matter on dwarf galaxies.
Visible Multi-Object Spectrograph (GMACS)
This instrument is a high throughput system designed to help observe particularly faint objects. Planned applications include studying the evolution of galaxies, verifying the number of stars in a given region, and studying chemical enrichment.
Near-IR IFU and Adaptive Optics Imager (GMTIFS)
GMTIFS is another spectrograph - noticing a pattern? - planned for the Giant Magellan Telescope. This uses a micro-mirror system to carefully format light and provides a broader visible spectrum. Its main goals include helping understand the formation of stars and planets, as well as the structure and assembly of early galaxies.
IR Echelle Spectrograph (GMTNIRS)
Like the previous instrument, this is designed to study things like young stellar objects, protoplanetary systems, and disks of debris. By providing useful information in a broader band of visible light, this tool is expected to provide far more efficiency in its observations.
Facility Fiber Optics Positioner (MANIFEST)
Getting light to the spectrographs is vital for creating useful images. However, most of the proposed instruments won't use the full field of view available. If they don't, why not make use of the extra space? That's where the Many Instrument Fiber System (MANIFEST) comes in. In effect, the Giant Magellan Telescope will be able to examine multiple targets at the same time without sacrificing image clarity.
Given the in-demand nature of powerful telescopes, this makes an incredible observatory even more desirable. Looking at more things in the sky means more science will get done and more studies can be completed on time.
How Much Does All Of This Cost?
About $1 billion. The US is leading the partnership, but it's also being supported by Australia, Brazil, and South Korea in various ways. Chile acts as the host country - which is arguably more important than financial support. After all, telescopes aren't very useful if we put them in the wrong spot!