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A daily view of all the goings-on at ASTRON and JIVE.

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  • 04/08/18--17:00: WinCC OA, The Navigator
  • © Henk Mulder, Arthur Coolen

    You may have heard somebody mention WinCC OA (or the Navigator) in the corridors, meeting rooms and plenaries a few times now. Or had a quick glance at it in the control-room. If you have not, you probably should take some time out of your schedule and have a look..

    The LOFAR infrastructure has been monitored successfully all these years by a SCADA (Supervisory Control and Data Acquisition) system, where all the details from software level, TBB boards, fan speeds, power levels, broken tiles, observations running (you name it..) are being displayed, trended, archived and alarmed. There is extensive daily System Health Management going on to make sure we get the best out of LOFAR, and for this we use the WinCC OA system by Siemens.

    This is also the place where the Operators turn off (and on after repair) all the elements that have issues like oscillation, fallen over LBA antennas, summator noise, etc., and abort observations that have a mayor problem after they have started. They also use it to keep an eye on the stations in and outside the Netherlands and get alerted to critical system problems before they happen, like crashed software, full hard discs, failing Rubidiums/power supplies and other equipment in the field cabinets.

    WinCC Open Architecture is a SCADA system for visualising and operating processes, data/production flows, machines and plants in many lines of business. For us it allows us to track and monitor thousands of data-points throughout LOFAR in one system. It is also used by countries and companies for giant projects like transportation systems, gas, water and energy distribution, or complete factory processes (for instance Gasunie and CERN). The whole CERN research installation including every data-point of all the installations over the 27-kilometer ring of the LHC is monitored and controlled by WinCC OA.

    The monitoring is developed and designed in-house and is being updated constantly as LOFAR grows with each new station and upgrade. It has become a piece of monitoring software that is invaluable for making sure we keep LOFAR the best large telescope network.

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    © Colloquium

    (NB: Note the unusual day!)

    Investigating the origin of cosmic magnetic fields is a key science driver behind the Square Kilometre Array (SKA). With the typical sensitivity predicted for surveys with the SKA, it should be possible to probe magnetic fields in the Universe statistically, using a grid of rotation measures (RMs).

    Historically, the majority of large polarimetric surveys have been performed in the 21cm band, with poor frequency sampling and limited sensitivity, dramatically hindering the accuracy with which RMs can be recovered. In the current era of the SKA precursors, however, observers have access to low-frequency instruments that are both highly sensitive and possess large fractional bandwidth, enabling high Faraday-space precision.

    In this talk, I will present the first results from the POlarization from the GLEAM Survey (POGS) project. This is an ongoing effort to exploit the excellent sky coverage and unparalleled fractional bandwidth of the Galactic and Extragalactic All-sky MWA (GLEAM) survey to extract a catalog of sources that are linearly-polarized at low frequencies. I will present a catalog of polarized sources detected at 200 MHz, including measured Faraday depths and polarization properties.

    Polarized sources detected by the MWA at 200 MHz as part of the POGS project, overlain on the Oppermann et al. (2014) map of Galactic Faraday depth. The initial region covered in this talk is bounded by the dashed contours, with the sign of the source FD indicated by the marker color, and the size scaled according to the magnitude of the FD. The GLEAM survey boundary is denoted by the dot-dashed contour.

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    This year, the ASTRON/JIVE PV started out strong with a meeting attended by more than forty members. For comparison, last year's headcount was a meager fourteen - we attribute the improvement to the copious number of cookies we used as bait. ;-)

    The highlight of the meeting was a lively presentation of the various activities planned for this year. Whether you're an intellectual, an adventurer, or something in between, you're bound to find something to your liking in the programme.

    As usual, the list of activities was turned into a poster displayed on the ground floor of the building. However, this year we weren't satisfied with simply listing the activities and adding some nice pictures, but created a puzzle instead. The first one to send in the correct solution qualified for a very special prize: German sausages accompanied by a pot of extremely hot mustard!

    The picture shows the glorious moment of Juergen (the puzzle's intellectual father and the one who drove all the way to Germany to buy the sausages) presenting the award to Jan Kragt, the lucky winner.

    Congratulations, Jan, and a year full of exciting activities to all PV members!

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    © Alice Allen

    Source codes are increasingly important for the advancement of science in general and astrophysics in particular. Journal articles meant to detail the general logic behind new results and ideas often do not make the source codes that generated these results available, decreasing the transparency and integrity of the research. The Astrophysics Source Code Library (ASCL) is a registry of scientist-written software used in astronomy research. In this presentation, I will discuss what software is suitable for inclusion in the ASCL, how to submit software to the resource, and the benefits of doing so. I will also cover what happens after software is submitted, how ASCL entries are indexed by ADS, the links between literature and software entries, and how having an ASCL ID for your software can be used for citing your code.

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  • 04/12/18--17:00: A LOFAR map of W50 and SS433
  • © Jess Broderick et al.

    W50 (sometimes referred to as the Manatee Nebula) is a Galactic supernova remnant, approximately 20,000 years old, and located 18,000 light years away. At the centre of W50 is the X-ray binary SS433, whose precessing jets are thought to be responsible for the observed 'ear-like' structures in W50, which has overall dimensions of about 2 deg x 1 deg.

    Although the W50/SS433 system has been the subject of numerous studies in the literature, only a few of these investigations were carried out at low radio frequencies. Therefore, in 2013-2014, we conducted an observing campaign of W50 and SS433 in the LOFAR high band (centred at 150 MHz) as part of the Transients Key Science Project, with our main goal to characterise the low-frequency properties of radio flares from SS433. In addition, we obtained a detailed map of W50 at an angular resolution of about 1 arcmin, and we also detected a wealth of structure along the nearby Galactic plane, including the most complete detection to date of the radio shell of the supernova remnant G38.7-1.4.

    The low-frequency morphology of W50, with its complex structure of arcs and filaments, is generally in excellent agreement with previously published studies at higher frequencies. We find additional evidence for spectral turnover in the eastern wing, potentially due to foreground free-free absorption. SS433 is tentatively variable at 150 MHz, with an observed rise in flux corresponding to extended flaring activity at higher frequencies. Further details of our study can be found in the recently published paper Broderick et al. 2018, MNRAS, 475, 5360 ( ).

    LOFAR, with its excellent low-surface-brightness sensitivity, is facilitating novel Galactic science at low radio frequencies. Many exciting results can be expected in the future from, for example, the LoTSS and MSSS surveys.

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  • 04/15/18--17:00: R&D department outing 2018
  • © ASTRON

    On Thursday 5 April, the R&D department traveled North to visit the beautiful city of Sneek.

    The first part of the afternoon was spent at Lankhorst Engineered Products.

    After coffee and an introductory talk, we were treated with four factory tours, visiting several specific areas of the large facility. Topics ranged from volume-production to client-specific, small series items.

    Guided by skilled Lankhorst staff, we were able to ask many questions and were provided with lots of in-depth information.

    We're looking forward to Lankhorst-staff visiting ASTRON in the near future.

    The second part of the afternoon was spent at Lokaal55, where excellent food was served, during a very entertaining pubquiz, provided by Quizbroers.

    The winning team (#3) are now the proud owners of the ASTRON Pubquiz Trophy!

    Thanks for joining us during this enjoyable afternoon.

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    © JIVE

    It was a question that the JIVE team took to the European Week of Astronomy and Space Science 2018 from 2nd - 6th April in Liverpool, UK.

    The answer was an open one, with responses delivered by a global audience. A host of talks and posters throughout the week featured VLBI in relation to gravitational waves, Fast Radio Bursts, black holes and the SKA, to name but a few topics.

    A special session on Wednesday 4th April encouraged attendees to consider the impact and growing potential for VLBI in radio astronomy: 'Exploring the Universe: A European vision for the future of VLBI'. The session was organised by Tiziana Venturi (INAF), Zsolt Paragi (JIVE), and Michael Lindqvist (Onsala Space Observatory), as part of the JUMPING JIVE project (Joining up Users for Maximizing the Profile, the Innovation and Necessary Globalization of JIVE). It was well attended and included lively and insightful discussions.

    Alongside the talks and posters, JIVE also partnered with e-MERLIN, ALMA, DARA (Development in Africa with Radio Astronomy) and ICE (Interferometry Centre of Excellence) to produce a radio astronomy exhibition corner. This area showcased the range of work being done across the institutes, and crucially, introduced a broad audience to the possibilities of VLBI – leaving them to ponder "What can VLBI do for my research?"

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    © AENEAS-project

    On 26-28 March 2018, the AENEAS (Advanced European Network of E-infrastructures for Astronomy with the SKA) project had its second all-hands meeting. This time we visited the Observatoire de la Cote d'Azur (OCA) in Nice, France. The photo shows the participants of this meeting in front of the Astronomical observatory, built by Charles Garnier and Gustave Eiffel on top of Mont Gros, Nice, in 1881.

    Besides the usual status updates and parallel sessions for Work Package face-to-face meetings, we had several presentations by astronomers involved in the SKA Science Working Groups (SWG) to discuss the functionality the SKA Regional Centre (SRC) network will need to provide in order to support their science. Although the scientists came well prepared to describe their science cases, it was clear from the discussion that the translation into what is needed to support extracting science from the raw data was far from complete. Following the presentations by the SWG group members, there was a lively discussion section that proved a good starting point for the work for the coming months where this interaction with the science community will intensify and a full gap analysis will be compiled to understand what we do not yet know as well as how to solve the challenges we do know.

    At the next all-hands meeting, in October 2018 in Bologna, we will give an update on this ongoing discussion with the SKA Science Working Groups as well as the evolving detailed requirements for the SKA Regional Centre (SRC) network.

    The AENEAS project started in January 2017 and runs for a total of three years. The ultimate objective of the AENEAS project is to develop a concept and design for a distributed, federated European Science Data Centre (ESDC) to support the astronomical community in achieving the scientific goals of the Square Kilometre Array (SKA). AENEAS brings together all the European member states currently part of the SKA project as well as potential future EU SKA national partners, the SKA Organisation itself, and a larger group of international partners including the two host countries Australia and South Africa. AENEAS is funded by a EU H2020 grant.

    More information on the meeting can be found at

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    © Saintonge et al. 2017, ApJS, 233, 22

    Observations of molecular gas in distant galaxies are experiencing a coming-of-age, transitioning from a "discovery" to a "survey" mode. New and upgraded facilities are now making it possible to survey molecular gas efficiently in large galaxy samples, and these observations are proving to be critical in refining our general picture of galaxy evolution.

    In this talk, I will review recent results from the two largest surveys for molecular gas in normal star-forming galaxies, the z=0 IRAM-30m COLD GASS survey and the z=1-2 IRAM-PdBI PHIBSS survey, and show how they combine to lend strong support in favour of the "equilibrium" model for galaxy evolution, under which most of galaxy evolution is regulated by gas inflows and outflows, and by the efficiency of the star formation process.

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    © JIVE

    The Colombo radio telescope in Azores (Portugal) participated, for the first time, in a geodetic Very Long Baseline Interferometry (VLBI) experiment on 21st February 2018, together with the 40m radio telescope at the Yebes Observatory (Spain).

    The successful observations in S (2 GHz) and X (8 GHz) bands were confirmed after data recorded by both telescopes was sent to JIVE for further analysis and correlation.

    "This result has been long sought, the Colombo radio telescope is in a very strategic location for VLBI. The intense team work demonstrates great technical capability, and the importance of international cooperation”, says Paco Colomer, JIVE Director.

    Colombo is a 13.2m radio telescope at the RAEGE station in Santa Maria (Azores), while the 40m radio telescope at Yebes Observatory is operated by the Spanish National Geographic Institute (IGN). Colombo is the second telescope that will constitute the Spanish-Portuguese Atlantic Network of Geodynamic and Space Stations (RAEGE).

    RAEGE is a project of the IGN and the Regional Government of the Azores consisting of a network of 4 Fundamental Geodetic Stations located in Yebes (Guadalajara, Spain), the Azores Islands (Santa Maria and Flores, Portugal) and the Canary Islands (Gran Canaria, Spain), It is integrated into the International VLBI Service for Geodesy and Astrometry (IVS), which, among other objectives, measures the movements of terrestrial tectonic plates, the Earth Orientation Parameters (EOP), the length of day (LoD), and constructs the International Celestial Reference Frame (ICRF).

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    "Astronomical communication is a good way to make friends and find peace in the world" - Dr. Kazanuri Shibata, President of the Astronomical Society of Japan.

    With this uplifting statement the biannual 'Communicating Astronomy with the Public (CAP)' conference began; where 450 communicators, astronomers and researchers from around the world had convened under the cherry blossom in Fukuoka, Japan to share ideas and discuss projects from 24-28 April.

    Against the bustling backdrop of the city's new science museum, best practices in science communication, innovation in education and projects that promote inclusivity and diversity were all on the agenda. Iris Nijmen (ASTRON) and Gina Maffey (JIVE) both attended to share some of the ongoing work from the Dwingeloo perspective.

    Iris gave a talk about challenges and new ideas to communicate about radio astronomy, and Gina presented how she found her way into JIVE and started to communicate about VLBI in new ways. Together with Eleonora Ferroni from INAF, Iris also gave a workshop about communicating for big research infrastructures, like the Square Kilometre Array, in non-hosting countries. During the workshop, press officers and communicators from many other astronomy collaborations were present, such as ESO, ALMA, and other SKA countries.

    Highlighting the opportunities and challenges of working across teams and borders the talks and workshop delivered by both Iris and Gina struck a chord with many of those attending the conference.

    The opportunity to connect with the international community at a conference such as this, and make friends, certainly ensures those challenges seem are a bit more approachable.

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    © ASTRON

    Once upon time, there was a manager in a highly innovative company with the idea to create a large banner with a picture of the superterp in Exloo.'Think big', he probably thought. He requested Monique to take care of this challenge at a size of 6 x 3 meters. While the people of the communication department designed the final picture, Monique looked for the options for such a large banner at an affordable price and at short notice. It seemed that everything could be realised within a week, just before the required deadline of Wednesday morning.

    On Tuesday afternoon, with a one-and-a-half-day of delay in delivery, the frame of the banner was ready for assembly. Soon, the people of the mechanical group discovered that six spare parts were missing so the supplier received a call from the purchase department to solve the problem. They promised an urgent delivery the same evening of these missing elements.

    The next day, early in the morning, the second attempt for assembly... Luckily, no further hiccups occurred and as you can see in the picture, the result really was impressive (and ready just in time).

    This could not have been realised without the help of the real heroes in this story: Roy, Jorrit, Henri, Johan, Jesper, Albert, Sjouke, Mike, Gerda and Monique!

    It was just another day at the office; never a dull moment...

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    This year, the ASTRON/JIVE PV started out strong with a meeting attended by more than forty members. For comparison, last year's headcount was a meager fourteen - we attribute the improvement to the copious number of cookies we used as bait. ;-)

    The highlight of the meeting was a lively presentation of the various activities planned for this year. Whether you're an intellectual, an adventurer, or something in between, you're bound to find something to your liking in the programme.

    As usual, the list of activities was turned into a poster displayed on the ground floor of the building. However, this year we weren't satisfied with simply listing the activities and adding some nice pictures, but created a puzzle instead. The first one to send in the correct solution qualified for a very special prize: German sausages accompanied by a pot of extremely hot mustard!

    The picture shows the glorious moment of Juergen (the puzzle's intellectual father and the one who drove all the way to Germany to buy the sausages) presenting the award to Jan Kragt, the lucky winner.

    Congratulations, Jan, and a year full of exciting activities to all PV members!

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    © Bill Saxton (NRAO)

    The millisecond pulsar PSR J0337+1715 is in a 1.6-day orbit with an inner white dwarf companion, and the pair is in a 327-day orbit with an outer white dwarf companion. This hierarchical triple provides an excellent laboratory to test a key idea of Einstein's theory of gravity, the strong equivalence principle (SEP): do all objects, even those with strong gravity like neutron stars, fall the same way in the same gravitational field? Almost all alternative theories of gravity predict violations of the SEP at some level. We have carried out an intensive program of timing this pulsar, and we are able to perform a very sensitive test of the SEP. I will discuss our methods, our result, and its theoretical implications.

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  • 04/26/18--17:00: Girlsday 2018
  • © ASTRON

    On April 12, 2018, 32 girls visited ASTRON for the annual Girlsday.

    From soldering and coding, to building galaxies with 3D pens, and searching for pulsars with the Dwingeloo Telescope: the programme, in collaboration with JIVE, NOVA and CAMRAS, offered many fun hands-on activities.

    This year the girls came from the dr. Nassau College in Assen, De Nieuwe Veste in Coevoerden, Wolfsbos in Hoogeveen and CSG Dingstede in Meppel.

    I want to thank everyone who participated to make this years' Girlsday such a great event!

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    © ASTRON

    From Monday 26 through Wednesday 28 of March, we had an extremely successful and fruitful workshop at ASTRON to discuss the recent progress in the exciting field of radio galaxies. Such radio sources emit so much energy that it affects the life of the host galaxy. The workshop covered results from observations at many different wavelengths, and from theory. A lot of time was dedicated to the discoveries that the new low-frequency facilities are now making possible.

    The about fifty participants formed a very interesting mix, including many expert astronomers and leaders in the field of radio galaxies, but also many enthusiastic young students and postDocs attended. The programme gave the opportunity to everybody to have a lot of interaction during coffee breaks, lunches and over a drink!

    Particularly nice was to see that, without having to do any extra effort, 22 of the 51 participants and speakers were female. The group photo (which shows this lively mix of attendees) was taken during an impromptu visit to the Dwingeloo telescope guided by Paul Boven and Michel Arts: thanks to them for making thispossible.

    We now have all the presentations on-line, have a look at this web page if you are interested.

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  • 04/30/18--17:00: The Artefact
  • © ASTRON

    Every Tuesday at 14:00 the ARTS weekly meeting takes place in the Fish Bowl (Minnaert) room. We try to use most of the allotted hour brain storming our way out of problems we encounter along the way towards a shiny time-domain survey with Apertif. Using our varying expertise, and collective memory of problems solved in the past, we usually manage to Sherlock Holmes our way out. But in October 2017 Leon Oostrum noticed block-like periodic signals (left-most subpanel of the image) and determined these occurred at a 1.024 s period. Such signals are a serious problem, as they hamper the search for the periodic signals of new pulsars in the data.

    As 1024 ms is a oft-used number in the data packetisation, as early as in the Apertif Front End beam-former, we initially concluded the problem must originate elsewhere, upstream from our systems, or be caused by the data capture software we used on the GPU cluster. But after these were ruled out it became apparent we were creating The Artefact, as it was now known, ourselves. Somewhere. The literate reader may know that Sherlock Holmes excels in solving other people's problems, but is not actually all that self-aware. And that, precisely, was what solving our problem required now. And thus, week after week, Jonathan Hargreaves would produce new plots, like the 2nd subpanel, showing the incorrect patterns the data would sometimes make. Poring over numbers of missing bits here, and jumps in the data there, he was able to first pinpoint the problem to a single Uniboard (3rd panel), then to a specific FPGA, over the course of two months. With the offending FPGA identified (there are hundreds in the whole system), a trip to Westerbork confirmed his skills surpass Sherlock's -- the problem was of our own making: the FPGA had a memory module of the wrong type installed, and we had not checked. The firmware is optimized for a specific memory type to achieve the maximum throughput. This wrong module affected both imaging and time-domain Apertif data. After banishing and replacing the memory, the data looked clean.

    Case closed.

    Lessons learned: 1) Budget significant time for debugging your complex system. 2) Exploit time-domain data for telescope verification.

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  • 05/01/18--17:00: ASTRON Hackathon
  • © Cees Bassa

    We are entering a new era of astronomy with the massive radio telescope, the Square Kilometre Array (SKA), coming online in next five years. The SKA will generate around 160 TB (10^12 bytes) of data per second, which is more than 5 times the current global internet traffic.

    Such an immense data rate presents unparalleled challenges to astronomical and information technology communities in terms of data storage, transport, exploration, and accessibility. Amruta Jaodand (ASTRON/API) and Joe Callingham (ASTRON) organised a two-day hackathon (23-24th of April) to bring together academia and industry to address some of these challenges.

    Over the corse of the hackathon, projects were developed in using machine learning to classify galaxies, using Google Cloud Platform to simulate distributed processing of large data sets, production of industry standards of test vectors for large data sets, and parallelisation of code to speed up data processing.

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  • 05/02/18--17:00: 8 eyes of hairy inspiration
  • © PF

    When you think that you are quietly sitting in your office with the two of you, better think twice... there's always extra 4 pairs of eyes and extra thousand(s) of pairs of ears somewhere in the corner of your office.

    There he was, a visitor, hah! Peacefully sitting in an old-paper box. A handsome long-hairy-legged, 6.4 cm big undercover exoskeletal agent. Yep, it is a he - the prominent bulbous pedipalps in front reveal his readiness for courtship with one of his kind. Nothing special, just a friendly, innocent visit.

    Most of you would either kill such a creature or start screaming your lungs out, but have you ever examined such a beauty in detail? To me it is always a source of inspiration for many 'mechanical' ideas.

    Look at his super-sensitive trichobothria - tiny hair on his legs. They are spider's ears, tasting pupils and his nose in one (or in thousands since he has a hell lot of them all over the place) - independently detecting minuscule movement and responding to vibrations of the background noise in the 40-600 Hz bandwidth. The hair smells and tastes whether his prey is edible, and it helps him against falling. How marvellous is it, don't you think? Not only does he have 4 pairs of legs, but also extra thousand or so to stabilize just in case! (not a bit overconstrained don't you think ;-))

    *DISCLAIMER: no insect has suffered during this examination; to reduce the stress factor among the co-workers and the spider itself, the beauty was put back to its natural environment (outside)

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    © Baan

    The National Astronomical Research Institute of Thailand (NARIT) is building a new radio telescope, an 'updated' version of the 40-m Yebes telescope (IGN). The telescope will be located within the Huai Hongkhrai Royal Development and Study Centre (HHK), a nature reserve north of Chiang Mai which is part of the Thai King's domain. Besides the high-frequency Cassegrain-Nasmyth optics covering a frequency range 2 - 115 GHz, the new telescope will also have a low-frequency primary focus feed covering 330 MHz to 2 GHz. A collaboration with the Shanghai Astronomical Observatory may result in placing a VGOS telescope at the same site for geodetic observations.

    The Thai research community currently has expertise in pulsar studies, and star formation studies using molecular lines and masers. The new telescope will be used as a stand-alone research instrument as well as a VLBI station together with EVN in Europe (and surroundings), KVN in Korea, JVA and VERA in Japan, CVN in China, and hopefully LBA in Australia.

    An International Review Committee Meeting has been held in March at NARIT in Chiang Mai with members from befriended observatories in order to consider the design of the telescope and the plans for building the required instrumentation. Committee members came from OAN, NAOJ, SHAO, KASI, CSIRO, MPIfR, and also ASTRON. The accompanying photo shows the Review Committee around the 'hole in the ground' where the new telescope will be located.

    In preparation for the future, a NARIT-Sokendai Winter School 2018 has been held in January with teachers from Australia, China, Germany, Japan, Korea, the United Kingdom, and The Netherlands. The students of the school came from Thailand, Indonesia, Vietnam, and Philippines.

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