4MOST Low Resolution Spectrographs Characterization in Chile

Abstract

4MOST, the 4m Multi Object Spectroscopic Telescope, is the optical, fibre-fed, MOS facility for the VISTA telescope at ESO's Paranal Observatory in Chile. Its main science drivers are in the fields of galactic archeology, high-energy physics, galaxy evolution and cosmology. The 4MOST consortium consists of several institutes in Europe and Australia under leadership of the Leibniz-Institut fur Astrophysik Potsdam (AIP). This paper focuses on the successful testing, installation and technical commissioning of the Low Resolution Spectrographs (LRS-A and B) for the 4MOST instrument at ESO's Paranal Observatory, Chile. This work was completed on October 18. 2025. Details on the assembly, integration, and performance of both 4MOST spectrographs from their arrival in the integration hall through to the telescope installation are provided. Attention is given to the optimization of procedures implemented to enhance performance and meet the expected top-level requirements. The 4MOST LRS features 2436 fibres split into two low-resolution spectrographs LRS-A and LRS-B (1624 fibres, three arms, 370-950 nm, R > 4000) and one high-resolution spectrograph (812 fibres, three arms, ~44-69 nm coverage each, R > 18000). The fibre positioner covers a hexagonal field of view of ~4.1 deg2. The fibers are 85 μm core with an output beam at f/3. The Centre de Recherche Astrophysique de Lyon (CRAL) had the full responsibility for the two low-resolution spectrographs. Each of them is composed of an off-axis Schmidt collimator that produces a 200 mm beam, which is split into three spectral arms by dichroics and directed to F/1.73 cameras with standard 6k x 6k 15 microns pixel CCD detectors.

Characterization and on-sky testing of photonic, AWG-based astronomical spectrographs
Jeronimo Calderon-Gomez, Frantz Martinache, Nick Cvetojevic +14
arXiv28 Sep 2026PreprintarXiv licenceFull textInstrumentation & methodsarXiv
Inertial sub-range detection and characterization for ground-layer turbulence at new extremely large telescope sites in Chile
Marco Sepúlveda, Darío G. Pérez
arXiv5 Nov 2026PreprintarXiv licenceFull textInstrumentation & methods Atmospheric science & meteorologyarXiv
Semi-automated single-mode fiber coupling for AO-fed spectrographs
Aaron J. Crepp, Brian L. Sands, Justin R. Crepp
arXiv17 Sep 2026PreprintarXiv licenceFull textInstrumentation & methodsarXiv
Community Lessons from builders of infrared multi-object spectrographs
Solange V. Ramirez, Maren Cosens, Nicholas P. Konidaris II +21
arXiv20 Oct 2026PreprintCC BY-NC-ND 4.0Full textInstrumentation & methodsarXiv
Inverse-designed tapers to improve throughput of on-chip astrophotonic spectrographs
Vikram Seenivasan, Pradip Gatkine
arXiv17 Oct 2026PreprintCC BY 4.0Full textInstrumentation & methodsarXiv

Cite

BibTeX RIS

BibTeX

@misc{laurent20264most,
  title = {{4MOST Low Resolution Spectrographs Characterization in Chile}},
  author = {Florence Laurent and Didier Boudon and Eric Daguise and Remi Giroud and Aurelien Jarno and Alexandre Jeanneau and Andreas Kelz and Jens-Kristian Krogager and Victor Mauger-Vauglin and Jean-Emmanuel Migniau and Matthew Lehnert and Flora Paganelli and Arlette Pecontal and Emmanuel Pecontal and Alban Remillieux and Johan Richard and Allar Saviauk},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.01219},
  eprint = {2609.01219},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.01219},
  note = {CC BY-NC-SA 4.0},
}

RIS

TY  - UNPB
TI  - 4MOST Low Resolution Spectrographs Characterization in Chile
AU  - Florence Laurent
AU  - Didier Boudon
AU  - Eric Daguise
AU  - Remi Giroud
AU  - Aurelien Jarno
AU  - Alexandre Jeanneau
AU  - Andreas Kelz
AU  - Jens-Kristian Krogager
AU  - Victor Mauger-Vauglin
AU  - Jean-Emmanuel Migniau
AU  - Matthew Lehnert
AU  - Flora Paganelli
AU  - Arlette Pecontal
AU  - Emmanuel Pecontal
AU  - Alban Remillieux
AU  - Johan Richard
AU  - Allar Saviauk
PY  - 2026
DA  - 2026/09/01
PB  - arXiv
DO  - 10.48550/arxiv.2609.01219
UR  - https://arxiv.org/abs/2609.01219
AB  - 4MOST, the 4m Multi Object Spectroscopic Telescope, is the optical, fibre-fed, MOS facility for the VISTA telescope at ESO's Paranal Observatory in Chile. Its main science drivers are in the fields of galactic archeology, high-energy physics, galaxy evolution and cosmology. The 4MOST consortium consists of several institutes in Europe and Australia under leadership of the Leibniz-Institut fur Astrophysik Potsdam (AIP). This paper focuses on the successful testing, installation and technical commissioning of the Low Resolution Spectrographs (LRS-A and B) for the 4MOST instrument at ESO's Paranal Observatory, Chile. This work was completed on October 18. 2025. Details on the assembly, integration, and performance of both 4MOST spectrographs from their arrival in the integration hall through to the telescope installation are provided. Attention is given to the optimization of procedures implemented to enhance performance and meet the expected top-level requirements. The 4MOST LRS features 2436 fibres split into two low-resolution spectrographs LRS-A and LRS-B (1624 fibres, three arms, 370-950 nm, R > 4000) and one high-resolution spectrograph (812 fibres, three arms, ~44-69 nm coverage each, R > 18000). The fibre positioner covers a hexagonal field of view of ~4.1 deg2. The fibers are 85 μm core with an output beam at f/3. The Centre de Recherche Astrophysique de Lyon (CRAL) had the full responsibility for the two low-resolution spectrographs. Each of them is composed of an off-axis Schmidt collimator that produces a 200 mm beam, which is split into three spectral arms by dichroics and directed to F/1.73 cameras with standard 6k x 6k 15 microns pixel CCD detectors.
ER  -

Abstract

Related

Cite