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The European organisation ESO has embarked on the construction of the Extremely Large Telescope (ELT) in the middle of the Chilean desert. The telescope and its structure reach a volume comparable to eight times that of the Arc de Triomphe in Paris.

A monster of technology

The collecting power of its ultra-giant mirror, 39 metres in diameter, is equivalent to bringing together the 16 largest telescopes in the world. When it is built, probably shortly after 2026, the ELT will be able to observe the weakest sources in the sky. It will be able to study objects so far away that they are inaccessible to other telescopes, unlocking many mysteries in cosmology, about the formation of galaxies, for example the nature of small galaxies or star clusters far beyond our Galaxy or Local Group.

Moreover, since the resolving power of a telescope depends on its size, the ELT will be able to solve the stars with the smallest apparent sizes: the apparent size of the most distant galaxies is much smaller than an arcsecond (for comparison, the Moon’s apparent size is 1800 arcseconds). At these scales, observations are very much affected by the Earth’s atmospheric turbulence, requiring advanced techniques to overcome it, such as adaptive optics.

From the outset of the project, ESO has made a huge commitment to focus all its efforts on ensuring the highest possible spatial resolution. This is equivalent to counting the petals of a daisy 100 kilometres away! The goal is to distinguish an extrasolar planet from its star to distances approximately the thickness of a spiral arm of our Galaxy, in order to study in detail the planetary content of a considerable number of nearby and less nearby stars.

 

It’s a gamble that’s not insignificant since the main mirror will be made up of 798 segments, each 1.40 metres long, which will have to be aligned with an unequalled precision of only 15 millionths of a millimetre! The other four mirrors of the telescope will have to guarantee the same precision. In particular, two of these mirrors can be mechanically deformed to compensate for tiny variations in the path of light due to atmospheric turbulence. This is made possible by adaptive optics based on complex turbulence analysis systems.

Faced with the challenge of building a mastodon telescope capable of resolving the smallest sources of light in the universe, the European organisation ESO took an even riskier gamble: first install the most sophisticated instruments capable of obtaining the finest spatial resolutions, and only then the two instruments that use the telescope’s maximum collecting power instead (this being guaranteed, whatever the performance of the telescope and its enormous structure).

 

Click here to wiew the article (pdf)

 

Abstract

Nearby dwarf galaxies are local analogues of high-redshift and metal-poor stellar populations. Most of these systems ceased star formation long ago, but they retain signatures of their past that can be unraveled by detailed study of their resolved stars. Archaeological examination of dwarf galaxies with resolved stellar spectroscopy provides key insights into the first stars and galaxies, galaxy formation in the smallest dark matter halos, stellar populations in the metal-free and metal-poor universe, the nature of the first stellar explosions, and the origin of the elements. Extremely large telescopes with multi-object R=5,000-30,000 spectroscopy are needed to enable such studies for galaxies of different luminosities throughout the Local Group.

Conclusion

"We recommend the construction of ELTs with multi-object spectrographs to enable archaeological study of dwarf galaxy formation histories across the Local Group."

9-13 septembre 2019, Rome

link to the website of the conference

Scientific Rationale

In the next decade, the commissioning of Extremely Large Telescopes (20-40m class) will allow us to see the high redshift universe using new eyes of unprecedented power. By themselves or in combination with other facilities, these new eyes will have the potential to transform our understanding of the formation and early evolution of galaxies and black holes, first light and cosmic reionization, as well as the evolution of the intergalactic and circumgalactic media

Link to the site of the conference.

SCIENTIFIC RATIONALE

                The European Extremely Large Telescope (ELT) will be the world’s largest optical/IR facility for at least a generation. As it is currently the case for the European Very Large Telescope (VLT), the MOSAIC multi-object spectrograph will be the workhorse instrument for the ELT.

The proposed MOSAIC multi-object spectrograph will be the workhorse instrument for the future Extremely Large Telescope (ELT), the biggest visible/infrared telescope in the world. It will be the world-leading multi-object spectrograph well into the 2020s, contributing to most fields of contemporary astronomy. Scientists from across the world are meeting in Toledo to explore the unprecedented capabilities of MOSAIC in tracking the earliest ‘first-light’ structures in the Universe, and to refine proposals for observations that will uniquely trace the amounts of dark and invisible matter in the deep Universe.

  • Produced by Lightcurve Films
  • Direction, Concept, Text, Post Production : Maarten Roos (Lightcurve Films)
  • Graphical Animation : Dick Peterse (ScienceMedia.nl)
  • Voice Over : Pamela van de Wal
  • Voice Over & Translation Services
  • Original Music Score : William Zeitler
  • Scientific Advisor : Francois Hammer et al.

We are attending SPIE Astronomical Telescopes + Instrumentation in Austin this june 2018. SPIE is an international society advancing an interdisciplinary approach to the science and application of light. You will find below our contribution to the event. Feel free to download our material.

Paris, Tuesday 3rd October 2017

The MOSAIC multi-object spectrograph will be the workhorse instrument for the future Extremely Large Telescope (ELT), the biggest visible/infrared telescope in the world. It will be the world-leading multi-object spectrograph well into the 2020s, contributing to most fields of contemporary astronomy. Scientists from across the world are meeting in Toledo to explore the unprecedented capabilities of MOSAIC in tracking the earliest ‘first-light’ structures in the Universe, and to refine plans for observations that will uniquely trace the amounts of dark and invisible matter in the deep Universe (see video).

The Multi-Object Spectrograph, also known as MOSAIC, is a proposed instrument for ESO’s forthcoming Extremely Large Telescope (ELT). MOSAIC is currently in the initial project stage known as Phase A. The study contract was signed at the Paris Observatory on 18 March 2016 by ESO and the CNRS–INSU, the leading technical institute in the MOSAIC consortium. The consortium includes institutions from five countries (France, United Kingdom, The Netherlands, Brazil and Germany) with six associated partners (Austria, Finland, Italy, Portugal, Spain and Sweden).

Read the article on the ESO website

 

17-19th October 2017 – Toledo, Spain

Scientific Rationale

The Extremely Large Telescope (ELT) will be the world's largest optical/IR facility for at least a generation. It will have an immense collecting area, equivalent to gathering together all the current large telescopes in use today. Multi-object spectroscopy will be a key capability of the observatory, immediately able to harness its unprecedented sensitivity to deliver unique surveys which address a broad range of important topics in contemporary astrophysics.

The conceptual design of MOSAIC, a powerful multi-object spectrograph for the ELT, will conclude in late 2017. The design combines high-multiplex near-IR and visible spectroscopy, together with AO-corrected spectroscopy in the near-IR that exploits the fantastic angular resolution of the ELT across a large field of view. These capabilities will enable MOSAIC to tackle fundamental questions, e.g. pertaining to the formation and evolution of galaxies, which are simply out of reach of other facilities.

This colloquium is timed to discuss the scientific opportunities of surveys with MOSAIC, focussing in particular on simulated performances from the conceptual design. It will also take stock of other developments that will influence surveys envisaged for the late 2020s.

Visit website : https://www.mosaictoledo.org/

The next important meeting for MOSAIC will be the MTR (Mid-Term Review) meeting in Garching - Germany (near Munich) at the ESO headquarters (European Southern Observatory). This meeting will take place on Tuesday 21st and Wednseday 22nd of March 2017. You can follow the news on the ELT project at this adress on the ESO web page.

Who are we? Infos on the MOSAIC consortium.

CONSORTIUM

Scientific goals and milestones: why MOSAIC?

SCIENCE

How do we get there? All the technology behind MOSAIC.

INSTRUMENT

What performance can we expect from MOSAIC?

PERFORMANCE

How will MOSAIC fit in the instrumental landscape?

SYNERGY