4MOST - 4-metre Multi-Object Spectroscopic Telescope
4-m Multi-Object Spectroscopic Telescope


4MOST first spectra


The 4MOST High-Resolution Spectrograph (HRS) has now reached "first light" (or first spectra) in the Landessternwarte (Heidelberg) lab for the green channel with an engineering grade detector. This is not only a major and exciting milestone for the project in general, but it also means that for the first time we have real HRS data to work with after many years of working with simulated data. It is also a validation of many aspects of the 4MOST opto-mechanical design, which allows the project to move forward with the remaining MAIT activities with increased confidence.

Walter Seifert (HRS Lead Engineer) reports: "The basic alignment of the channel with regard to wavelength range, image quality and spectral resolution has been performed in two days without any issues. Further iterations on optimising the performance will be done with the actual science detector in place. Nevertheless, the spots are already in or close to specification. Apart from flatfield and spectral arc exposures using the lab calibration unit, we also took a spectrum of the sun by holding an auxiliary fibre out of the window towards the sky."

Roelof de Jong (4MOST PI) commented: "I am very excited to see these first spectra from the High-Resolution Spectrograph. It is wonderful to see that within a few days of effort the team is already meeting most specifications. This gives great credit to the many excellent people involved from across the consortium: the HRS team of course, but also the detector and control hardware teams, the fibre team, and now the data management system team. I want to thank them all for their dedicated efforts."

Left: HRS spectrum of a ThAr lamp. The full wavelength range of the green channel (516 – 573 nm) is shown for a few central fibres. Right: image quality test using the ThAr spectra. Shown are 100 × 100 px at the four corners of the detector as well as some intermediate points.

HRS solar spectrum. The full wavelength range of the green channel (516 – 573 nm) is shown for a few central fibres.

4MOST Wide Field Corrector optics delivered


The 4MOST Wide Field Corrector (WFC) and Atmospheric Dispersion Corrector lenses have been manufactured and tested at KiwiStar Optics, New Zealand. These are large lenses that represent a significant part of the overall hardware budget for 4MOST. The Project Manager, Joar Brynnel, is pleased to report that five of the six WFC lenses have just arrived safely at the UCL laboratory, where they will be integrated with the WFC mechanics and aligned with high precision in order to meet their tight specifications. The sixth lens is still at KiwiStar in the final stage of manufacturing. It is a great relief for the project that the lenses have arrived without damage. Peter Doel (UCL) reports: "The crates have arrived safely and are under lock and key in the lab. No external shock indicators were triggered and there was no visual damage of the boxes. We very briefly (and without taking them out of the boxes) did a visual inspection of the lenses before resealing them. The lenses look fine."

This picture shows the lens "L3" in its transport box during incoming inspection at UCL.

Changes to Survey leadership


The science programme of 4MOST is driven by its individual Surveys, each pursuing different science cases. Currently, there are ten such Surveys to fill the Guaranteed Time Observations of the Consortium, each under the leadership of one or more Survey Principal Investigators (PIs). After 10 years of serving as Survey co-PI of the Milky Way Halo Low-Resolution Survey (S1), Prof. Amina Helmi has unfortunately decided to resign from this position. The 4MOST Project is very grateful for her leadership since the start of the project and for bringing the Survey to its current excellent state together with her S1 co-PI Prof. Mike Irwin. Amina is looking forward to seeing data arrive in a few years' time and will remain involved in the further development and exploitation of the Survey. We wish Amina all the best for her other endeavours and the responsibilities she has taken on.

Fortunately, Amina's resignation will not leave a vacancy. The Project is extremely pleased that the 4MOST Executive Board has approved the nomination of Prof. Else Starkenburg as the new co-PI of the Milky Way Halo Low-Resolution Survey at its meeting on 15 October 2020. This is expected to be a fairly smooth leadership transition, as Else already served as one of the co-PIs of S3, the Milky Way Disc and Bulge Low-Resolution Survey (4MIDABLE-LR), in the past, and is hence already familiar with the required background. While Else will remain active within 4MIDABLE-LR, its leadership is now in the hands of the remaining S3 Co-PIs Dr. Cristina Chiappini and Dr. Ivan Minchev.

The Project would like to thank everyone involved in this transition for the excellent leadership provided so far, and is looking forward to the continued collaboration toward the final development of the survey programme, science operations and data exploitation.

4MOST All Hands Meeting 2020


The 4MOST Consortium came together on 05 – 09 October 2020 for its sixth annual All Hands Meeting (AHM). Originally planned to be held at ESO in Garching, the ongoing Corona pandemic forced the event to be held entirely online.

The AHM brought together consortium members working to define, construct, operate and scientifically exploit the 4MOST Facility. This included the engineers, managers and scientists responsible for the delivery of the 4MOST Facility, the scientists planning the science operations in the infrastructure working groups, and the scientists from the large number of institutes involved in defining the ground-breaking consortium science surveys.

From a project management perspective, the project is generally in good shape. Funding for hardware is secured and a moderate contingency is available. The hardware budget has seen only a minor increase of about 2% over the past year. As already reported in this news channel, the project has incurred a schedule delay of 9 months as a result of Covid-19, this delay was however expected and is comparable to delays in other projects. It was noted that the three parts of the project (Facility, Operations, and Science) continue to be well synchronized schedule-wise. Sustained travel restrictions due to the pandemic means that many activities such as progress meetings and acceptance testing have to be re-cast into a remote format. The project risk register was updated during the AHM, some risks could be retired, and several risk indexes were updated.

On the facility side of the project, a particular focus of the meeting was to discuss and coordinate subsystem and system integration activities. The thrust of discussions was distinctly different from that of the past AHM, showing that we are making progress towards the system testing phase at the AIP. Substantial effort has gone into preparing the AIP infrastructure for carrying out the system-level testing between now and Preliminary Acceptance Europe (PAE).

The Operations Development Group (ODG) used the AHM to make progress in two essential directions. In the area of observation preparation, the front-end, new simulations run with the 4MOST Facility Simulator (4FS) were presented and discussed extensively. As more functionality is added to the 4FS discussions tackled both possible tweaks to the survey strategy and the surveys' target catalogues, as well as the development and understanding of algorithmic solutions to on-going issues. Concerning the overall data flow, ODG is currently running Operational Rehearsal 2, designed to run most pipelines for the first time on simulated-real data. All pipelines showed their current products. Discussions revolved around the necessary improvements in each pipeline to make those products "not-wrong", or, in other words, good enough to be sent onward to the next pipeline, while not necessarily being correct in all aspects yet. Other discussions at the AHM revolved around ways to add more resources to some struggling work packages, as well as closing the formal loop on operations requirements.

The meeting's programme can be found here.

4MOST Final Design Phase formally closed


An announcement from the Project Manager, Joar Brynnel:

On 22 – 24 September 2020 a meeting between the 4MOST project and ESO was held at the AIP in Potsdam. The purpose of the meeting was to discuss the updated System (Optical) Alignment Plan and the Focal Surface Test Tools (FSTT) Design Report and associated action items. Those documents were formally reviewed at the 4MOST delta-FDR in January 2020, a review which resulted in some action items that were classified as critical. This meant that the delta review was not formally closed, which by extension meant that the Final Design Phase was not closed.

ESO, in the meeting represented by Jeff Pirard and Stephane Guisard, determined that the documents have now been substantially improved, and that most of the critical action items could be closed. At the end of the meeting a statement was made by ESO management that the 4MOST Final Design Phase is now officially concluded. While it is recognized that most subsystems have been in the MAIT phase for some time already, it is nevertheless an important milestone for the project overall. Many thanks to everyone involved in making this happen!

New top-level schedule


An announcement from the Project Manager, Joar Brynnel:

As with numerous other projects, the restrictions caused by Corona did not leave 4MOST unscathed. In spite of diligent efforts we have incurred schedule delays, not the least for engineers and technicians working on site in integration facilities. In addition, we have experienced numerous delivery delays from vendors and manufacturers. In aggregation, this has led to an updated top-level schedule with the following new dates: Preliminary Acceptance Europe (PAE) is now scheduled for October 2022 (delayed by 8 months), while Preliminary Acceptance Chile (PAC) is now scheduled for August 2023 (delayed by 9 months).

Consortium members can download the updated top-level schedule from DocuShare.

Successful second 4MOST community workshop


On 9 – 14 July 2020, ESO and the 4MOST consortium jointly organised the second 4MOST community workshop Planning for 4MOST: toward the 4MOST survey programme. Due to the ongoing COVID-19 pandemic the workshop was held entirely online.

Following ESO's request for "Letters of Intent for Public Spectroscopic Surveys" (LoIs) from the ESO community, and the review of the submissions by ESO's Public Survey Panel (PSP), the successful teams have been invited to submit a detailed proposal in December 2020. The purpose of this workshop was to support the teams behind the successful LoIs in preparing their proposals, and to facilitate a well-matched and efficient joint 4MOST survey programme.

In a total of 12 presentations, the 4MOST consortium provided the participants with up-to-date information on the 4MOST operations, survey strategy, available tools to prepare their proposals and data processing pipelines, while ESO described the further selection process. In turn, 19 successful LoI applicants presented their proposed community surveys, focusing in particular on their operational requirements.

A number of question and discussion sessions, as well as a dedicated slack workspace, provided the opportunity for the 210 registered participants to discuss and clarify any remaining issues, and to jointly prepare for the integration of potential Participating Community Surveys into the 4MOST Science Team.

Introducing the new Operations Scientist


The new Operations Scientist: Peder Norberg

An announcement from the Principal Investigator, Roelof de Jong:

I am very pleased to announce that the extragalactic leader of the Survey Strategy Infrastructure Working Group (IWG2), Peder Norberg, has been appointed to to the newly introduced position of Operations Scientist. The role of the Operations Scientist is to coordinate the development of the survey strategy for the 4MOST survey programme. This includes setting requirements to the 4MOST Operations Model to satisfy the scientific needs of the surveys in terms of survey strategy. It also includes a coordinating role in the development of the relevant software tools, in particular all modules of the 4MOST Facility Simulator, and in the running of relevant simulations. The Operations Scientist is therefore the bridge between the Survey Strategy IWG (and thus the science needs of the Survey teams), the Operations System, and the Operations System Engineers.

Please give Peder all your support in his new (and old) role.

Workshop announcement: Planning for 4MOST – toward the 4MOST survey programme


4MOST is a state-of-the-art, high-multiplex, fibre-fed, optical spectroscopic survey facility currently under construction for ESO’s 4-m VISTA telescope. During the first five years of operations 4MOST will be used to execute a comprehensive, integrated programme of both Galactic and extragalactic Public Surveys. The 4MOST survey programme will consist of both Consortium Surveys and Community Surveys, ideally with a high degree of complementarity, both scientifically and in terms of observing efficiency. The process of selecting the Community Surveys was initiated by ESO in November 2019 by requesting "Letters of Intent for Public Spectroscopic Surveys" (LoIs) from the ESO community. Successful applicants have been invited by ESO to submit full proposals in December 2020.

ESO and the 4MOST Consortium are now jointly organising an online workshop to take place in the period 9-14 July 2020. This workshop is open to all team members of successful LoIs, both for Participating and Non-Participating Surveys, and ESO strongly encourages at least some representation at the workshop from all invited surveys.

The purpose of this workshop is to support the teams behind the successful LoIs in preparing their proposals, and to facilitate a well-matched and efficient joint 4MOST survey programme. Specifically, the goals of the workshop are:

  • to provide the invited teams with up-to-date information regarding the selection process
  • to provide the invited teams with an opportunity to present their operational requirements and to discuss their integration into the 4MOST operational model
  • to provide the invited teams with an introduction to the available tools to prepare their proposals (e.g. 4FS)
  • to foster scientific collaborations and to prepare for the integration of potential Participating Community Surveys into the 4MOST Science Team.

Due to the current situation, the workshop will be held entirely online. It will be split into four sessions, each lasting for approximately 4 hours, to be held on 9-10 and 13-14 July 2020. The timing of the sessions will take into account the different time zones of the participants to the extent that this is possible.

Invited participants should register on the workshop's website.

Fibre positioner integration


On 27 April 2020, Scott Smedley reported that the AESOP fibre positioner reached a significant milestone. All 2,448 spines were installed in their final configuration. Almost the entire AESOP team (comprising 24 people) were involved in the assembly and testing of spine modules. All 28 spine modules successfully passed their unit tests. System testing will commence once all four electronics cabinets are fully assembled and integrated with AESOP.

All 28 spine modules have passed unit testing and been integrated into AESOP.

The AESOP focal surface comprises 2,436 science spines + 12 guide spines + 24 fiducial probes.

A team of two dozen engineers and technicians is involved in the design, manufacturing, assembly and testing of each spine module. This picture shows Sufyan Baker, one of the team's mechanical technicians.