The first meeting of the Board of Trustees of the European Solar Telescope Canarian Foundation took place online on September 19, 2023.

The main governing body of the European Solar Telescope Fundación Canaria is its Board of Trustees. This body shall represent the Foundation and shall exercise all the powers necessary to achieve the Foundation's aims. The Board of Trustees shall administer with due diligence the patrimony of the Foundation, maintaining their productivity according to the economic and financial criteria of a good manager.

During its first meeting on September 19, 2023, the Board of Trustees went through the usual steps required by this type of organisations. In this meeting, all the Trustees confirmed their acceptance of their positions and the representatives of the main executive bodies were chosen. In this way, Manuel Collados was elected as President of the Board of Trustees and Peter Gömöry as Vice-President. The President and the Vice-President, together with trustees Jorrit Leenarts, Svetlana Berdyugina and Robertus von Fay-Siebenburgen were elected to conform the Executive Committee of the Foundation.  

The President shall, among other duties, represent the Foundation Board of Trustees in all areas of its activities, coordinate and promote the activity of the Foundation, developing its internal regulations. The Vice-President shall be responsible for substituting the President in the event of illness, absence or inability to act on the part of the President and those functions that the Foundation statutes or the President may entrust to him.

The Executive Committee is in charge of the examination of all documentation to verify compliance with the budget and the accompanying explanatory report, as well as the adoption of appropriate measures to correct any deviations that may occur. It shall also carry out all activities delegated or entrusted to it by the Board of Trustees.

In addition, in this first meeting the Board of Trustees decided upon key aspects necessary to start with the running of the newly created entity, such as the formalisation of the steps for the legal registration of the Foundation and the approval of the processes to appoint the Director and Administrator.

The EST consortium members have participated in several outreach activities during the last months, reflecting efforts to raise awareness of the EST project at local and regional level.

Public event 'Un sole, Nessun Sole, Centomila Soli' in Venice (Italy). Credit: Luis Bellot/ IAA-CSIC.

The Association of Spanish Researchers in Norway organised the event ‘Tapas of Science’ on May 8, where Ada Ortiz (Expert Analytics AS), delivered an informal talk about the Sun and EST, titled "A tour of the Sun, so close, so mysterious." Ada was also interviewed on the radio program "Gente despierta" by the Spanish public radio broadcasting company RNE. During the interview, she explained various details about the EST project and solar research to the audience.

On June 23 and 24, the Slovak Academy of Sciences celebrated its 70th anniversary with a weekend full of outreach activities designed for science enthusiasts. At the stand reserved for the Astronomical Institute of the Slovak Academy of Sciences in the square in front of Eurovea (Bratislava), EST material was showcased, including a model produced with a 3D printer.

During the public event “Un sole, nessun Sole, centomila Soli” held on September 12 at the '900 Museum in Mestre, Italy, the EST documentary "Reaching for the Sun" was screened in English with Italian subtitles as part of the international conference "Sun in Science and Society". This event was organised by the EIE Group and the SOLARNET project.

In addition to the documentary screening, the audience engaged in discussions focused on the science and technology of EST.

EST also had a presence at the opening of the interactive exhibition "Sole" which took place on September 16. It is the result of the collaboration between the Istituto ricerche solari Aldo and Cele Daccò (IRSOL) and scientific mediators from L'ideatorio of the Università della Svizzera italiana (USI).

Interactive exhibition 'Sole' in Lugano, Switzerland. Credit: Renzo Ramelli / IRSOL.

The EST project was a partner of the exhibition and contributed to the proposal submitted to the Swiss National Science Foundation. Promotional material from EST was displayed at the entrance. In the same way, during the European Researchers' Night 2023 held on 29 September, brochures and posters featuring information about the EST project were distributed to visitors and interested people at the stand of the Instituto de Astrofísica de Andalucía (IAA-CSIC) set up in Granada.

The most recent event took place in Granada, Spain, from October 25 to 27 It was the IX Spanish Congress on Social Communication of Science, where over 400 communicators from different parts of Spain and South America gathered to discuss current challenges in social science and share best practices. During the event, Luis Bellot (IAA-CSIC), presented the organisation and execution of the school competition "The Sun at a Glance", which was conducted in the framework of the PRE-EST project.

IX Spanish Congress on Social Communication of Science (Granada, Spain). Credit: Ana Tamayo.

EST in the media

With the establishment of the EST Canarian Foundation on July 25, a common pan-European communica­tion strategy was devised. Each of the partner institutions translated the EST press release into their respective lan­guages and sent it to local, regional and national media.

This news raised significant interest among the media, resulting in over 70 articles published in online newspapers and specialised magazines. It received 7 mentions on radio and television. Ap­proximately 10 online newspapers from other countries such as India, Portugal and Australia also covered the news. Links to the press releases published by each institution in their respective languages can be found on the news section of the EST website.

The announcement also garnered considerable attention and visibility on social media. Posts related to the es­tablishment of the foundation reached over 10000 people and surpassed 700 interactions on the official EST social media accounts. In addition, the part­ners and the press published a total of 35 and 20 posts respectively on X, Facebook, Instagram and LinkedIn, covering the establishment of the EST foundation.

On September 16, during the press conference held on the occasion of the 80th anniversary of the first observation made at the Skalnaté Pleso Observatory, the State Secretary of the Ministry of Education of Slovakia provided strong support to EST, stating that "The European Solar Telescope is therefore one of the very important steps to preserve independence in the security of Europe and Slovakia, especially in connection with the current geopolitical situation."

A week later, Peter Gömöry, vicepresident of the EST-CF Board of Trustees, presented the Astronomical Institute of the Slovak Academy of Sciences on the Slovak public TV broadcasting corporation RTVS and took the opportunity to discuss EST.

Interview with Peter Gömöry on the Slovak public broadcasting channel RTVS.

EST website update

In the last six months, work has been carried out to update the EST website.

Firstly, a new section on the EST Canarian Foundation has been set up. It contains information on the goals of the foundation and its governing structure, with brief resumees of the Board of Trustees members. News related to the EST foundation are compiled in that section as well.

On the technical side, the descriptions of some EST systems and subsystems have been updated to reflect the current preliminary design status. This includes the EST image gallery, where new 3D renders, high-resolution images, and animations have been integrated and old images from the 2011 conceptual design have been archived. For instance, both the long and short versions of the video developed by IDOM, showing the structure, pier and enclosure of the future telescope, are now available.

Pictures from the updated EST image gallery website.

Furthermore, a new website section has been created specifically for the mini-series 'Here Comes the Sun', the audiovisual project developed by the University of Rome Tor Vergata. Among the resources available on the website are behind-the-scenes photographs taken during the filming process, the series trailer, and its five episodes, each accompanied by downloadable English and Italian subtitles.

Finally, additional materials and resources have been added to the EST documentary section on the website. These include 3D infographics produced for the documentary as well as footage captured by drones at various European observatories.

All resources available on the website are accessible and can be downloaded and utilised under a Creative Commons international license.

JAVIER LEÓN

AUTOMATION AND CONTROL ENGINEER

Javier holds a bachelor’s degree in Industrial Electronics and Automatic Control Engineering from Universidad de La Laguna, and a Master’s degree in Industrial Computing and Automation from Universitat Politécnica de Valencia. He has years of experience in industry, working on R&D projects for redox flow batteries as an automation and control engineer.

He joined the IAC in 2021 as a software engineer for the New Robotic Telescope (NRT), developing its low level control system, and joined the EST team in October 2023 as an automation and control engineer, in charge of the telescope control.

 

AMANDA LÓPEZ

COMMUNICATION OFFICER

Amanda holds a degree in Audiovisual Communication from the University of Granada, a Master's degree in Graphic Design from the University of La Rioja, and a Master's degree in Social Communication of Scientific Research from the International University of Valencia. She has experience in the field of scientific communications, having worked in the Scientific Culture and Innovation Units of the Universities of Granada and Cantabria, and the Communication Unit of Parque de las Ciencias.

Amanda joined the EST project in July 2023 as the new EST Communication Officer.

 

NICOLÁS RODRÍGUEZ

ELECTRONICS ENGINEER

Nicolás has a degree in Industrial Electronics Engineering and Automation from University of La Laguna, a Master’s degree in Industrial Engineering and a Master’s degree in Automatic Control and Robotics from Technical University of Catalonia. He has experience working for the Institut de Robòtica i Informàtica Industrial, a joint Research Center of CSIC and UPC, as research support Eegineer for the European project LOGISMILE and for the national project ROCOTRANSP.

Nicolás is now part of the EST team, working as control engineer for the Multi- Conjugate Adaptive Optics testbench.

 

ESTHER SORIA

OPTICAL ENGINEER

Esther holds a degree in Optics from the University of Zaragoza, complemented by a Master's in Optical and Imaging Technologies from the Complutense University of Madrid. Esther embarked on her professional journey with a two-year stint as a dedicated researcher at the CSIC. Driven by a passion for advancing scientific knowledge, Esther then pursued her PhD at the IAC. Her doctoral research focused on the development of new wavefront sensing techniques, specifically tailored for applications in the realm of astronomy.

Esther recently joined the EST team as an optical engineer.

 

The conceptual optical design of the three Tunable Imaging Spectropolarimeter/Fixed-Band Imager instruments foreseen for EST has been completed in 2023.

Figure 1. Conceptual layout of the TIS/FBI instrument.

The Tunable Imaging Spectropolarimeters and Fixed-Band Imagers (TIS/ FBIs) are one of the key instruments foreseen for the European Solar Telescope (EST). The development of the TIS/FBIs is carried out by a consortium formed by the Spanish Space Solar Physics Consortium (S3PC) —led by Instituto de Astrofísica de Andalucía (IAA-CSIC)—, University of Rome Tor Vergata (UNITOV), the National Institute of Astrophysics of Italy (INAF), University of Catania (UNICAT), Stockholm University (SU), Queen’s University Belfast (QUB), Mullard Space Science Laboratory (UCL-MSSL), Istituto di Ricerche Solari (IRSOL), and Leibniz-Institut für Sonnenphysik (KIS).

The TIS/FBIs will be responsible for providing maps of the thermal, dynam­ic and magnetic properties of the solar photosphere and chromosphere over a circular field of view of 60 arcsec at very high cadence and diffraction-lim­ited spatial resolution. To achieve this goal, they will measure the four Stokes profiles of selected spectral lines by means of a Fabry-Pérot etalon system.

Three TIS/FBIs will be built to cover the following spectral ranges: 390-500 nm, 500-780 nm, and 780-850 nm. Each instrument will be able to observe different spectral lines, typically four to five. This capability grants them exceptional versatility, enabling the simultaneous observation of multiple combinations of three lines. Moreover, the instruments will combine two different operation modes. In one mode, they will work as tunable narrowband spectropolarimeters (TIS mode). In the other mode, they will work as context fixed band imagers (FBI mode).

TIS/FBI concept

The conceptual layout of the instruments is depicted in Figure 1. Light coming from the telescope will first illuminate a filter wheel hosting a set of pre-filters centred about the wavelengths of interest. These filters will let pass a very narrow part of the spectrum (about 0.1 nm) into the instrument. Then, the transmitted light will be divided between the TIS (90- 95%) and the FBI (5-10%).

The TIS will modulate the incoming light polarimetrically with two liquid crystal variable retarders (LCVRs) and will scan the spectral line selected by the pre-filter with a system of two Fabry-Pérot interferometers that will achieve a spectral resolution of 5-10 pm, depending on the wavelength.

Finally, a polarising beam splitter will divide the modulated beam into two orthogonal polarisations that will be recorded by two cameras in order to reduce seeing-induced crosstalk. The FBI is much simpler, as spectral and polarimetric analyses are omitted. In this case a focused channel will be used for image reconstruction through the Multi-Object Multi-Frame Blind Deconvolution (MOMFBD) technique and for alignment of the TIS. A defocused (auxiliary) channel will observe the same scene with a difference of phase (phase diversity) in order to increase the capabilities of the MOMFBD technique.

The TIS arm

The three TIS instruments foreseen for the European Solar Telescope will record the spectrum of the four Stokes parameters of the incident light with a resolving power larger than 50.000, excellent (diffraction-limited) optical quality, and a polarimetric sensitivity as high as 10^-3 thanks to the use of dual-beam polarimetry.

Figure 2. Optical design of the TIS/FBI instrument. F3 is the telescope focal plane. FW stands for filter weel, BS for beam splitter, FP1 and FP2 are the two etalons, IM is an intermediate image, and FP represents the final focal plane.

The TIS optical design is depicted in Figure 2. Right after the filter and the beam splitter that divides light between the TIS and the FBI (Figure 1), two group of lenses will produce a slow (f/150) telecentric image of the solar scene. The dual Fabry-Pérot system will be placed close to this intermediate image. Illuminating the etalons with such a large f-number will prevent the harming pupil apodisation effects that appear in this (telecentric) configuration from being too large. Finally, another two groups of lenses will produce a telecentric image with the required plate scale and size on the detector.

One of the major advantages of this design is that no folding mirrors are needed. As a consequence, light absorption in the entire optical system is minimised, which increases the photon flux on the focal plane and, hence, reduces the time needed to achieve the required signal-to-noise ratios. In fact, thanks to the high throughput of both the telescope and the TIS instrument, scanning of a spectral line at 10 wavelength positions will take less than 20 seconds in most cases, according to the photon budget calculations that have been performed by the TIS team.

The main downside of this design is probably that the slow telecentric beam of f/150 requires the etalons (and also the optics) to have diametres of the order of 18 cm, several times larger than those used by similar ground-based instruments. No doubt, manufacturing such large etalons with high optical quality will be one of the biggest challenges of the project.

The FBI arm

FBIs will be employed to make broadband (0.1-0.5 nm) photometric observations of the solar surface with larger signal-to-noise ratio —and potentially faster cadence— than the TISes. These observations will then complement the measurements taken by the TISes, thereby increasing the flexibility and the overall capabilities of the instrument.

One noteworthy potential of the FBIs is their capacity to infer the wavefront degradation introduced by the instrument and the telescope in real time, as well as the residual atmospheric aberrations produced by seeing which are not corrected by the telescope adaptive optics system. The combined effect of these two sources of wavefront degradation is expected to reduce the final image quality. The ability to infer the wavefront error allows for subsequent compensation during image restoration with the MOMFBD technique.

To accurately sense the aberrations introduced by the instrument, the FBI and TIS optical paths must be as similar as possible. Ideally, the FBIs should be an exact replica of the TISes. However, the two largest doublets seen in Figure 2 have a very limited impact on the aberrations, as their focal length is much larger than that of the other lens groups. Aberrations produced by optical elements placed close to an image plane (etalons, filter wheel, LCVRs and beam splitter) will also be negligible, as the footprint of the incident beam on them is very small. Thus, only the first and last groups of TIS lenses must be replicated in the FBI, effectively reducing the size of the FBI arm by a factor of 4.

The current TIS/FBI design results in three 6 m x 1.5 m instruments (Figure 3). These dimensions are compatible with the envelope required to accommodate them into the Coudé room alongside other instruments. In view of the large size of the telescope, these dimensions are actually quite moderate.

Figure 3. Three-dimensional view of the TIS/FBI instrument.