The Thirty Meter Telescope, an undertaking of enormous proportions, is being built in Mauna Kea Hawaii. As the name implies the telescope will have a primary mirror with a 30 meter diameter. It will also have a secondary mirror with a diameter of over 3 meters, larger than primary mirrors on most telescopes. It will also have adaptive optics that will allow it to have incredible resolution power. If it is completed in time, in 2022, it could be the first of the new generation of Extremely Large Telescopes.
The primary mirror will consist of 492 smaller mirrors that will be precisely mounted and placed in proximity with each other to give the surface area of the 30 meter telescope. The mirrors will all each be individually actively controlled to work with the adaptive optics. The light gathering power of this enormous mirror will give the Thirty Meter Telescope 144 times more lighter gathering power than the Hubble Space Telescope.
The adaptive optics will the measure turbulence that is ever present in the atmosphere, as well as observing groups of stars. These measurements will than be used to be able to deform and adjust each mirror individually to compensate for and increase the resolution of the images coming into the telescope. These advantages will help to give the Thirty Meter Telescope 3 times better resolving power than one of the Keck telescopes.
The telescope will sport quite a few instruments that will be available for scientific observations. It will have a wide field optical spectrometer that will provide imaging and spectroscopy in the near-ultraviolet and the optical wavelengths. It will use precision cut focal plane masks to enable long-slit observations of single objects as well as short-slit observations many objects all at once.
There will also be an infrared imaging spectrometer that will be capable of diffraction-limited imaging and integral-field spectroscopy at the near-infrared wavelengths. And there will also be an infrared multi-object spectrometer allowing close diffraction-limited imaging and slit spectroscopy that will have a field of view with a 2 arc minute diameter in the near infrared wavelengths.
The telescope type will be a Ritchey-Chretien observatory with an altitude azimuth mounth. It will have a focal ratio of 15 when the secondary mirror takes the focal ratio 1 light coming from the primary mirror and it is converted to a focal ratio 15 beam. The overall field of view will be 20 arcminutes with a small vignetting around the edge of the image. Otherwise it will have a 15 arcminute field of view with full light.
The telescope location in Mauna Kea Hawaii was decided due to its excellent location and viewing conditions. The top of the volcano has a high enough elevation to be above the cloud cover and most of the turbulence in the air. The atmosphere is also really dry in the atmosphere above the telescope removing even more atmospheric pollution from the air. It is truly an incredible location for such a magnificent scientific instrument. The telescope started construction in July of 2014 and is planned for completion in 2022. When it is completed, whether the Giant Magellan Telescope is completed or not, the Thirty Meter Telescope will be the largest telescope with the largest mirror ever built.
About the auther: Rob C. is an amateur astronomer who runs the website My First Telescope you can read more about the Thirty Meter Telescope Here