Telescopio Nazionale Galileo
Encyclopedia
The Telescopio Nazionale Galileo, or TNG, is a 3.58m Italian
telescope
located on the island of San Miguel de La Palma (or, more simply, La Palma
), in the Canary Islands archipelago. It is one of the largest telescopes hosted by the Roque de los Muchachos Observatory
, a very important observing site in the northern hemisphere. It is now operated by the "Fundación Galileo Galilei, Fundación Canaria", a no-profit institution which manages the telescope on behalf of INAF, the Italian National Institute of Astrophysics. The telescope saw its first light in 1998.
Observations at the TNG can be proposed through the Italian Time Allocation Committee (TAC) which assigns, based on the scientific merit of the proposals, 75% of the available time. The rest of the time is at disposal of the Spanish and international astronomical communities. The TNG is open to new proposals two times a year, typically in March-April and September-October.
foci. It has a design derived from the New Technology Telescope
(NTT), an ESO
4-meters class telescope located in La Silla (Chile). Therefore, the optical quality of the telescope is ensured by an active optics
system performing real-time corrections of the optical components and compensating, in particular, for the deformations of the primary mirror, which is too thin to be completely rigid.
The interface between the telescope fork and the instruments at both Nasmyth foci is provided by two rotator/adapters. Their main function is to compensate for the field rotation by a mechanical counter rotation. The best quality of the TNG is that all the available instruments are permanently mounted at the telescope. This guarantees flexibility during an observing session, since it is possible to change instrument during the night with a loss of time limited to a few minutes.
The science based on observational data from the TNG is varied. Proposed observing programs go from the study of the planets and minor bodies of the solar system
up to researches of cosmological interest (e.g. large-scale structure of the Universe and systems of galaxies).
Decommissioned instruments:
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
located on the island of San Miguel de La Palma (or, more simply, La Palma
La Palma
La Palma is the most north-westerly of the Canary Islands. La Palma has an area of 706 km2 making it the fifth largest of the seven main Canary Islands...
), in the Canary Islands archipelago. It is one of the largest telescopes hosted by the Roque de los Muchachos Observatory
Roque de los Muchachos Observatory
Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands...
, a very important observing site in the northern hemisphere. It is now operated by the "Fundación Galileo Galilei, Fundación Canaria", a no-profit institution which manages the telescope on behalf of INAF, the Italian National Institute of Astrophysics. The telescope saw its first light in 1998.
Observations at the TNG can be proposed through the Italian Time Allocation Committee (TAC) which assigns, based on the scientific merit of the proposals, 75% of the available time. The rest of the time is at disposal of the Spanish and international astronomical communities. The TNG is open to new proposals two times a year, typically in March-April and September-October.
Technical characteristics
The TNG is an altazimuthal reflecting telescope with a Ritchey-Chretien optical configuration and a flat tertiary mirror feeding two opposite NasmythNasmyth telescope
The Nasmyth telescope, also called Nasmyth-Cassegrain, is a reflecting telescope developed by James Nasmyth. It is a modified form of a Cassegrain telescope, mounted on an alt-azimuth mount.-Scheme:...
foci. It has a design derived from the New Technology Telescope
New Technology Telescope
The New Technology Telescope or NTT is an Alt-Az, 3.58-metre Richey-Chretien telescope part of the European Southern Observatory and began operations in 1989. It is located in Chile at the La Silla Observatory and was an early pioneer on the use of active optics...
(NTT), an ESO
European Southern Observatory
The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
4-meters class telescope located in La Silla (Chile). Therefore, the optical quality of the telescope is ensured by an active optics
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, mechanical stress...
system performing real-time corrections of the optical components and compensating, in particular, for the deformations of the primary mirror, which is too thin to be completely rigid.
The interface between the telescope fork and the instruments at both Nasmyth foci is provided by two rotator/adapters. Their main function is to compensate for the field rotation by a mechanical counter rotation. The best quality of the TNG is that all the available instruments are permanently mounted at the telescope. This guarantees flexibility during an observing session, since it is possible to change instrument during the night with a loss of time limited to a few minutes.
The science based on observational data from the TNG is varied. Proposed observing programs go from the study of the planets and minor bodies of the solar system
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
up to researches of cosmological interest (e.g. large-scale structure of the Universe and systems of galaxies).
Scientific instruments
The TNG is equipped with three instruments:- DOLoRes ("Device Optimized for the Low Resolution"), CCD camera and low-resolution spectrographSpectrographA spectrograph is an instrument that separates an incoming wave into a frequency spectrum. There are several kinds of machines referred to as spectrographs, depending on the precise nature of the waves...
for observations in the visible band; - NICS ("Near Infrared Camera and Spectrometer"), camera and spectrograph for observations in the near-infraredInfraredInfrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
; - SARG ("Spettrografo ad Alta Risoluzione del Galileo"), high-resolution spectrograph for observations in the visible band.
Decommissioned instruments:
- OIG ("Optical Imager Galileo"), CCD camera dedicated to optical images at high resolution;
- Speckle camera, dedicated to observations in the visible band at the diffractionDiffractionDiffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word "diffraction" and was the first to record accurate observations of the phenomenon in 1665...
limit of the telescope;
- AdOpt@TNG, adaptive optics system working in the near-infrared.