The New Technology Telescope or NTT is a 3.58-metre

Ritchey–Chrétien telescope A Ritchey–Chrétien telescope (RCT or simply RC) is a specialized variant of the Cassegrain telescope that has a hyperbolic primary mirror and a hyperbolic secondary mirror designed to eliminate off-axis optical errors (coma). The RCT has a wi ...

operated by the

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 mem ...

. It began operations in 1989. It is located in

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

at the

La Silla Observatory La Silla Observatory is an astronomy, astronomical observatory in Chile with three telescopes built and operated by the European Southern Observatory (ESO). Several other telescopes are located at the site and are partly maintained by ESO. The obse ...

and was an early pioneer in the use of

active optics Active optics is a technology used with reflecting telescopes developed in the 1980s, which actively shapes a telescope's mirrors to prevent deformation due to external influences such as wind, temperature, and mechanical stress. Without active op ...

. The telescope and its enclosure were built to a revolutionary design for optimal image quality.

Characteristics

The main mirror of NTT is flexible and its shape is actively adjusted during observations by actuators to preserve the optimal image quality. The secondary mirror position is also actively controlled in three directions. This technology, developed by ESO, known as active optics, is now applied to all major modern telescopes, such as the Very Large Telescope at Cerro Paranal and the future European Extremely Large Telescope. The design of the octagonal enclosure housing the NTT is another technological breakthrough. The telescope dome is relatively small, and is ventilated by a system of flaps that makes air flow smoothly across the mirror, reducing turbulence and leading to sharper images. The NTT was the first telescope using what is now known as active optics: a feedback loop that actively keeps the (comparatively thin) monolithic mirror in shape, using numerous actuators on which the mirror is mounted. Its design as well as the design of its enclosure (the building protecting it) included many revolutionary features, from whence it was named. In particular, great care was taken to ensure a good ventilation of the telescope, and to avoid heat sources in around the telescope. Since its construction, the NTT has undergone several upgrades which continued to improve its quality. It was used as a real-life test bench for the engineering concepts and software used for the

Very Large Telescope The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, ...

. The New Technology Telescope initially had the same problem as the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

- the mirror was ground to the wrong shape due to a mis-calibrated

null corrector A null corrector is an optical device used in the testing of large aspheric mirrors. A spherical mirror of any size can be tested relatively easily using standard optical components such as laser, mirrors, beamsplitters, and converging lenses. O ...

. However, the active optics system of the NTT was able to correct that error without refiguring the mirror.

Instruments

Currently, the NTT is equipped with 2 instruments: *SofI ("Son of ISAAC", a VLT instrument), a near

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

camera and low-resolution

spectrograph An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify mate ...

, with

polarimetric Polarimetry is the measurement and interpretation of the polarization of transverse waves, most notably electromagnetic waves, such as radio or light waves. Typically polarimetry is done on electromagnetic waves that have traveled through or ...

and high-time resolution modes *EFOSC2 (ESO Faint Object Spectrograph and Camera, v.2), a

visible light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

camera and low-resolution spectrograph, with multi-object spectroscopy, polarimetry and

coronograph A coronagraph is a telescopic attachment designed to block out the direct light from a star so that nearby objects – which otherwise would be hidden in the star's bright glare – can be resolved. Most coronagraphs are intended to view ...

y modes

Science with the NTT

The NTT and its instrument have contributed for important discoveries since the telescope started working at La Silla. These include unravelling the mysterious Galactic centre, contributing to the observations of the first solar-like oscillations in another star, and breaking many distance records by finding new galaxies in the far-away Universe. Most recently, the NTT helped detect a disc around a massive young star, solving the mystery of star formation in massive stars, and its observations were crucial to determine how asteroids are modified by solar wind. NTT observations of stars orbiting the centre of our Milky Way helped determine the mass and the radius of its supermassive black hole, effectively helping to confirm the existence of such a massive and compact object.

References

External links

* {{European Southern Observatory Optical telescopes European Southern Observatory Articles containing video clips

Characteristics

Instruments

Science with the NTT

See also

References

External links