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Next generation distributed software and processing for LOFAR

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© (Copyright: A. Mechev)

LOFAR is a transformational pan-european radio telescope and a pathfinder for the Square Kilometre Array (SKA). LOFAR enables efficient surveys of the sky, targeting important astrophysical questions ranging from our solar system, to the formation and evolution of black holes and the large-scale structure of the universe. To enable these diverse studies, measurements for the Surveys Key Science Project (SKSP) are taken at a common resolution often superceding the needs of the individual user, but meeting the needs of the collective. However, this comes at the expense of increased data transport, storage capability in long term archives (LTA) and processing power.

To meet these challenges the radio recombination line (RRL) group and the SKSP, in collaboration with SURFsara, formed the LOFAR e-infra group; R. Oonk (PI: Leiden & ASTRON), A. Mechev (Leiden), N. Danezi (SURFsara), T. Shimwell (ASTRON & Leiden) and C. Schrijvers (SURFsara). The goal of this group is to bring the processing to the data by performing complex processing workflows within the LTA. We have realized this by creating the flexible and scalable LOFAR Reduction Tools (LRT) framework (Mechev et al. 2017) that is built on top of the LOFAR-DSP platform (Oonk et al. in prep). Together these are termed the LOFAR e-infra solution and enable highly automated LOFAR pipelines in the LTA (e.g. prefactor, ddfacet/killms, spectroscopy and preprocessing). The LRT framework was recently presented at the International Symposium on Grids & Clouds 2017 (Mechev et al. 2017, https://arxiv.org/abs/1712.00312 ).

The figure shows that the LOFAR e-infra solution weaves together the expertise of all organizations involved. We have processed over 300 LOFAR observations in 2016-2017 to science quality output, showing that we can match the observing rates for the SKSP and RRL surveys (Shimwell et al. in prep.; Oonk et al. in prep). The first science results, with many more to come, using this solution have now been published (e.g. Shimwell et al. 2016; Wilber et al. 2017). This work was carried out on the Dutch national e-infrastructure with the support of SURF Cooperative through grant e-infra 160022 & 160152.

* Figure: (Top) Data flow and massive parallelization of the prefactor pipeline on the high throughput Grid. The Calibrator 1 and Target 1 steps run concurrently as 244 independent jobs, whereas Calibrator 2 and Target 2 combine these results. (Bottom) Schematic of the dependencies of the LRT framework, the modules of the LOFAR DSP, and the infrastructure provided by the Netherlands Grid at SURFsara. Prefactor is just one of the available pipelines within the LRT.


A tale of two worlds

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© Lesley Goudbeek & Paula Fusiara

The electronics and mechanical worlds used to be relatively two different entities ...

Separated, all alone and lonely, fully occupied with their tasks in their own field of expertise: the one totally absorbed by the flat 2D world, while the other fully indulging themselves in the 3D space with all the degrees of freedom.

- "The Earth is flat!"

- "No, the Earth is round!"

Two different Computer Aided Design Software packages which do not really communicate with each other. E-CAD vs M-CAD ... try to import flawlessly all the files from one software package to the other the first time. You'd get a huge headache and your MCAD would have problems swallowing and processing all the tiny components ... not to mention not being able to do anything with your machine because it takes some time to load and translate everything from E to MCAD (long coffee break for you, or time for reading some already printed out articles ;-)). At the end, even if you succeeded importing all the ECAD and you wanted to place components and make 3D circuitry ... well ... ehm, it leaves a lot to be desired.

However, there is a light in the tunnel! The situation is slowly changing, and the flat world is turning more and more into the 3D space.

Very recently, one of the ASTRON's Electronics Engineers (Lesley) took part in an electronics CAD software workshop in Germany.

Nothing special you might think software like any other E-CAD. WRONG! The very first software package that combines the two worlds and allows you to route PCB layouts on an imported 3D body to make a 3D-MID part!

You will see it more often that a Mechanical Engineer (Paula) will also join the Electronics Engineer (Lesley) in attending such workshops/conferences: 3D Mechatronic Integrated Device Design and Manufacturing workshop to be exact. We were the only participants who represented both, the Electronics & the Mechanics, among all the attendees (Electronics Engineers).

The workshop was very interesting, and oh, boy! we had fun together: Lesley enjoyed routing his PCB layout and placing components on a 3D body for the first time (do not be fooled, 3D space can be tricky!), and me making my very first PCB layout and placing electronics components (yay!). We've learned a lot about metallization process, design rules, visited a production site of BETA Layout http://www.pcb-pool.com/ppus/info_pcbpool_3d_mid.html that does the 3D-MID prototyping, and of course we've seen the LPKF machine for 3D MID prototyping in action.

After all, we all know that the Earth is not flat at all ... disciplines are intertwined and we should learn from each other.

Great applause and thank you go to a small, family software company: engineering bureau FRIEDRICH who developed the TARGET 3001 MID PCB design software! (http://ibfriedrich.com/en/index.html

Watch this space ... it's just the beginning.

The tale of two worlds: status - to be continued :)

Westerbork milestone!

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© Henk Mulder, Richard Blaauw, Antonis Polatidis

This month Westerbork Observers reached a milestone!

Even after the end of the regular tied-array observations, the WSRT has continued to contribute to RadioAstron observations with RT1 and the MFFE (the most flexible and sensitive WSRT receiver). Recently the WSRT Observers have passed the milestone of making 1500 RadioAstron observations at 18cm, 6cm and 92cm.

This December alone, there will be 50 projects observed. The cryogenically cooled Multi-Frequency-Frontend (MFFEs) are currently used in RT0 and RT1, for VLBI, e-VLBI and s-VLBI (RadioAstron). The WSRT contributes significantly at 92cm (one of the few ground radio telescopes with this frequency). In the past, the observations where send by discpack to Russia, which could get lost during shipping. In order to make sure all the data arrives, we now built a system that sends it via FTP. Which still requires a lot of manual work for the observers. We are currently busy making an automatic system for this process.

Space VLBI: when we talk about very-long-baseline interferometry, people tend to think of EVN and other ground based arrays. But even more awesome is Space VLBI!

In the quest for even greater angular resolution, dedicated VLBI satellites have been placed in Earth orbit to provide greatly extended baselines. Experiments incorporating such space-borne array elements are termed Space Very Long Baseline Interferometry (SVLBI). The Spektr-R (or RadioAstron) project is funded by the Astro Space Center of Russia, and was launched into Earth orbit on 18 July 2011 from the Baikonur Space Center. The RadioAstron project is a radio interferometer composed of the Spectrum-R space telescope and terrestrial radio telescopes. The orbit height of the Spectrum-R is 390 thousand km, which makes it the longest radio interferometer to date. Russia's Spektr-R telescope is the largest orbital radio telescope and is in the by Guinness book of World Records. The "record" resolution is 8 micro-arcsec, at 22 GHz (in an H2O maser) on a 340,000 km baseline.

RadioAstron website:

http://www.asc.rssi.ru/radioastron/

Perentie - SKA Low Correlator and Beamformer

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© ASTRON + CSIRO

The SKA Central Signal Processor element is developed in a very international team. It is led by NRC (Canada) for both the SKA-Mid and SKA-Low. The sub-elements are designed by NRC and MDA (Canada), STFC (UK), AUT (New Zealand), CSIRO (Australia) and ASTRON (The Netherlands).

The SKA-Low CSP Correlator and Beamformer sub-element project (Perentie) bundles the engineering powers from AUT, CSIRO and ASTRON.

For the project members, this international constellation requires often joining teleconferences outside normal office hours as well as regular long distance travels for face-to-face meetings. During August and September both Leon Hiemstra and Koos Kegel joined CSIRO for several weeks to prepare for the Critical Design Review (CDR) planned early 2018. During our stay, the New Zealand team joined for a couple of days to take the opportunity to introduce a new team member. This close cooperation offers also a unique opportunity to learn from each other both from an engineering perspective but also from a cultural and social perspective. We joined the Australian Purple Day and have met the families during trips to the coast and the Blue Mountains.

Recently, Grant Hampson, John Bunton and Yuqing Chen visited ASTRON for three weeks to finish the CDR preparation. During this visit, Grant showed the CSIRO 2017 Collaboration Award for the Perentie team for the highly successful international collaboration with colleagues in The Netherlands and New Zealand to design and implement a high performance correlator and Beamformer.

The CDR documentation deadline is early January 2018: thanks to our fruitful collaboration we will certainly meet this date.

A tale of Two Worlds

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© Lesley Goudbeek & Paula Fusiara

The electronics and mechanical worlds used to be two different entities. Separated, all alone and lonely, fully occupied with their tasks in their own field of expertise: the one totally absorbed by the flat 2D world, while the other fully indulging themselves in the 3D space with all the degrees of freedom.

- "The Earth is flat!"

- "No, the Earth is round!"

They used two different Computer Aided Design Software packages which do not really communicate with each other. E-CAD vs M-CAD. Just try to import the files from one software package to the other. You'd get a huge headache and your MCAD would have problems swallowing and processing all the tiny components ... not to mention not being able to do anything with your machine because it takes some time to load and translate everything from E to MCAD (long coffee break for you, or time for reading some already printed-out articles ;-)). At the end, even if you succeeded importing all the ECAD and you wanted to place components and make 3D circuitry ... well ... ehm, it leaves a lot to be desired.

However, there shines a light at the end of the tunnel! The situation is slowly changing, and the flat world is turning more and more into the 3D space. Very recently, one of ASTRON's Electronics Engineers (Lesley) took part in an electronics CAD software workshop in Germany. Nothing special, you might think; software like any other E-CAD. WRONG! Here is the very first software package that combines the two worlds and allows you to route PCB layouts on an imported 3D body to make a 3D-MID part!

In the future, you will see more often that a Mechanical Engineer (Paula) will also join the Electronics Engineer (Lesley) in attending such 3D Mechatronic Integrated Device Design and Manufacturing workshops. This time we were the only participants who represented both worlds, the Electronics & the Mechanics, among all the attendees (Electronics Engineers).

The workshop was very interesting, and oh, boy! we had fun together: Lesley enjoyed routing his PCB layout and placing components on a 3D body for the first time (do not be fooled, 3D space can be tricky!), and me making my very first PCB layout and placing electronics components (yay!). We've learned a lot about metallization process, design rules, visited a production site of BETA Layout http://www.pcb-pool.com/ppus/info_pcbpool_3d_mid.html that does the 3D-MID prototyping, and of course we've seen the LPKF machine for 3D MID prototyping in action.

After all, we all know that the Earth is not flat at all ... disciplines are intertwined and we should learn from each other.

Great applause and thank you go to a small, family software company: engineering bureau FRIEDRICH who developed the TARGET 3001 MID PCB design software! (http://ibfriedrich.com/en/index.html

Watch this space ... it's just the beginning.

The tale of two worlds: status - to be continued :)

The view of Centaurus A from the Murchison Widefield Array

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© Radio image by Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM Team. MWA tile and landscape by Dr John Goldsmith / Celestial Visions. Red indicates the lowest frequencies, green the middle frequencies and blue the highest frequencies. Cen A image credit: ICRAR/Curtin.

Centaurus A is one of the truly iconic objects in the radio sky. It is a popular target for amateur astronomers in the Southern Hemisphere due to its size, elegant dust lanes, and prominent plumes. As the closest radio galaxy to Earth, "only" 12 million light-years away, for professional astronomers it is the perfect "cosmic laboratory" to study the physical processes connected to the presence of an active black hole. The radio lobes are 9 (nine!!!) degrees in size (18 times the size of the full Moon...): such a large size means that Centaurus A is one of the very very few objects in the sky where perspective should be taken into account!

Even for the Murchison Widefield Array (MWA) imaging this object is a challenging task. The large size of the radio emission in Centaurus A appears clear in the GLEAM survey, showing the "radio colour" view of the sky above the MWA radio telescope, located in outback Western Australia. The Milky Way is visible as a band across the sky. The Centaurus A radio galaxy is the object to the right of the image.

However, the latest addition to the study of this radio galaxy has been the combination of deep observations with the MWA (at 154 MHz) and the Parkes radio telescope (at 2.3 GHz) to image all the emission from Centaurus A and to derive the spectral properties of the huge radio lobes. The MWA has extremely good sensitivity for diffuse emission allowing the large-scale structure of Centaurus A to be imaged in great detail. The figure on the top left shows a greyscale of the emission of Centaurus A at 154 MHz with the MWA. The image is shown on a linear scale between -0.1 and 1.2 Jy/beam and has an angular resolution of 3 arcmin.

The observations at radio frequencies have been combined with those from several optical telescopes to study complex mechanisms fuelling jets of material blasting away from a black hole 55 million times more massive than the Sun.

The results can be found in the paper "The jet/wind outflow in Centaurus A: a local laboratory for AGN feedback" by McKinley, Tingay, Carretti, Ellis, Bland-Hawthorn, Morganti, et al. (https://arxiv.org/abs/1711.01751) and a press release from ICRAAR that can be found at https://www.icrar.org/galaxygiant/ .

Ger's Twinkling Quasar

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© astron

One highlight of Ger's scientific legacy is the radio source J1819-3845, better known as "Ger's Twinkling Quasar". In the beginning of 1999, Ger, together with Jane Dennett-Thorpe, discovered that this radio source was twinkling; it could change brightness by more than a factor two in less than an hour! Although a few radio sources were known that were varying slowly, the very fast variations of J1819-3845 were extremely unusual. And Ger being Ger (the more unusual something seemed, the more interesting it was to him!), he started to monitor J1819-3845. In the end, he followed the source for more than thirteen years and was able to derive some unique and bizarre astronomy from that.

It turned out that the twinkling was due to interstellar scintillation, meaning that the variations are not due to the source itself, but are caused by the light travelling through an inhomogeneous, turbulent interstellar medium in between J1819-3845 and us. Because of the extensive monitoring, Ger was able to derive many many properties of the intervening material and J1819-3845 has become a unique source of information about the interstellar medium. One of the very interesting facts is that the medium causing the brightness fluctuations turned out to be very close to us, about 5 lightyears away. This makes it one of the nearest objects to the solar system.

However, at some moment in 2006, J1819-3845 suddenly stopped twinkling. The most likely reason is that the medium causing the twinkling has moved out of the way and is not in front of the source anymore. But, as sudden the twinkling disappeared, it can also come back... For this reason, during the commissioning of Apertif we regularly observe J1819-3845, just to check whether it is still quiet, or that it has started again to twinkle.

So far, no twinkling has been seen with Apertif. The plot shows the light curve of J1819-3845 taken from the summary paper Ger and J.-P. Marquart wrote about the source, with a new point added from the Apertif observations. Compared to the older data, the source has faded a little, but the decrease is slow and steady, with no fast variations.

An unexpected Christmas package

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© Paula Fusiara, Lesley Goudbeek

Who doesn't like coming to their office in the morning and seeing an unexpected package? Indeed, I love unboxing the unknown... this rush of adrenaline streaming into your body while you carefully take an object out of the foil, connect the provided 9V battery, push the switch button on the prototype and voila!

The LEDs make an enchanting bright flash dance of joy on a 3D curvature... oh well, right, I made a small dance of joy and the LEDs were just "bright", ehm ehm :)

You MADE my day, BETA Layout , super huge THANK YOU! :)

Those of you who read my post on 18th December could have recognized the shape. Yes, together with Lesley we were learning how to route circuitry on this specific 3D body in 3D-MID design software package during the workshop, and now we have the physical prototype of our CAD model.

To colleagues who were wondering why there was a big smile on my face one day throughout the whole day: now you know the root cause :)

The curious ones among you who would like to get into the Christmas mood by looking at the 3D-MID LEDs alone, you can pass by Lesley's or mine office. For the time being, we have two of these little red LED-flashing gems fairly distributed between the two worlds. In January, Lesley and I will put one of these babes to the test.... I'm already utmost excited and looking forward to see whether the patient will survive our in-depth investigation.

Have a Merry Christmas! and once again BIG THANK YOU to Beta Layout for this wonderful Christmas surprise.


ASTRON Season's Greetings

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© ASTRON

On behalf of our Board, Management Team and all of our staff, we wish you a Merry Christmas and a Happy New Year! We are looking forward to a great 2018!

Season's Greetings from JIVE

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© JIVE

Season's Greetings from all at JIVE and the JIVE council!

Wishing everyone a happy holiday and all the best for 2018!

Milky Way simulations at SKA Calendar for December 2017

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© Background image adapted from an artistic impression of the Milky Way (R. Hur t: NASA/ JPL/Caltech, J. Green: CSIRO , J. Urquhar t: U. of Kent). Simulated Galactic methanol maser distribution made by L.H Quiroga-Nunez (Leiden/ JIVE), H. van Langevelde (JIVE/ Leiden) and M. Reid (CfA).

Trigonometric parallaxes and proper motions of masers associated with massive young stars have been used to determine the parameters of the Milky Way. In particular, the Bar and Spiral Structure Legacy (BeSSeL) survey has reported the most accurate values of the Galactic parameters so far. The determination of these parameters with high accuracy has a widespread impact on Galactic and extragalactic measurements.

Simulations of 6.7 GHz methanol masers are aimed at establishing the confidence with which the Galactic parameters can be determined. This is relevant for the data published in the context of the BeSSeL survey collaboration, but also for future observations, in particular from the southern hemisphere, like the SKA.

The image for December in the SKA calendar 2017 shows a simulation of Galactic methanol maser distribution made in JIVE. The simulations were developed by Luis Henry Quiroga Nunez (Leiden/JIVE), Huib van Langevelde (JIVE/Leiden), Mark Reid (CfA) and James Green (CSIRO). The researchers have simulated the population of maser-bearing young stars associated with the Galactic spiral structure, generating several samples and comparing them with the observed samples used in the BeSSeL survey. Consequently, they have checked the determination of Galactic parameters for observational biases introduced by the sample selection. The results of this investigation has been published in A&A 604, 72 (2017) by Quiroga-Nunez et al.

Image: Top view of the Milky Way showing simulations of massive star forming regions in the Galaxy that will be observable with the SKA1-mid telescope (in orange) with Northern radio interferometers such as the VLBA (in blue).

Jan Idserda retired

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© Harm-Jan Stiepel

Jan Idserda, crowned as "Meester Instrumentmaker", has retired on 24 December 2017. Many colleagues, former colleagues, business relations and a former teacher of the LIS(*) said goodbye during a big reception.

In his 42 years at ASTRON, Jan was involved in many constructions and designs for the various telescopes and instruments. As a real LIS graduate, he was continuously developing himself, up to and including CNC milling, and nowadays 3D printing. We are pretty sure that he will continue his art in his own workshop at home, and will make even more beautiful constructions.

Jan, thanks for 42 years of great work for ASTRON, and for being a great colleague.

(*) Leidsche Instrumentmakers School. This famous school was founded by Nobel Prize winner Heike Kamerlingh Onnes, who discoverd super-conductivity in 1911.

Hiddo Hanenburg retired

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© Ronald Halfwerk, Johan Pragt

Hiddo Hanenburg has retired on 26 december 2017. Many colleagues have said goodbye during a nice party.

Hiddo's career at ASTRON and NOVA started as mechanical designer for the MIDI instrument for the VLT-I, the first optical interferometer in astronomy that really did work.

After this very succesful instrument, Hiddo worked for an impressive number of other instruments (15 projects in his 17 year career at ASTRON), with a wavelength coverage from 370 nanometer to 10 meter.

Hiddo, thanks for the great work for NOVA and ASTRON, and for being a nice colleague. And also for your very successful "in-house green climate project".

Stewing White Rabbits

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© Paul Boven

As part of the JIVE contribution to the SADT consortium, I have been working on the design of absolute time (UTC) distribution for the SKA1 telescopes. White Rabbit is an open standard and open design for the distribution of time and frequency reference signals, and can achieve sub-ns accuracy on links of up to 10km. The links in the SKA will be much longer (up to 175km of fiber) and some of the equipment will be exposed to the harsh temperature changes of the semi-desert SKA locations. To still meet the required timing accuracy of 2ns requires the use of wavelength stabilized lasers (using DWDM optics) and external wavelength multiplexing filters.

Of course, such a design needs to be thoroughly tested. And so, in the days leading up to Christmas, several pieces of White Rabbit hardware got stewed, frozen, and stewed again. The ASTRON climate chamber was programmed to cycle from 0°C to 50°C and back in hourly steps of 10°C, while holding some of the parts that make up a White Rabbit link.

The image shows the complete distribution system as designed for the SKA. It consists of a White Rabbit distribution switch (in white, on the left), and underneath it, an enclosure holding the wavelength filters. Above are a time interval counter to measure the link performance and 2 spools of 10km fiber each. Inside the climate chamber (on the right) is the White Rabbit end-point, about to experience its first taste of what winter and summer will be like, in rapid succession.

The graph shows that the repeated temperature changes don't bother our White Rabbit system too much. The effects of the temperature steps are clearly visible, but are small compared to the required accuracy.

We gratefully acknowledge the ASTRON R&D group for their support and equipment.

Some changes at the R&D department of ASTRON

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© R&D

Last year, the R&D MT and some scientific members analysed the functioning of the R&D department. Several areas in the department were identified that could be improved in order to reach the long-term goals of the R&D department in a better way. After a careful process of discussing several solutions within the R&D MT, the ASTRON MT and with a positive advice of the Workers' Council the following changes will be effective from January 1st, 2018:

- The current competence group Systems Design and Integration (SD&I) will be transformed into a new Competence Group 'Systems Engineering & Project Management' (SE&PM).

- The Technology Transfer Office will be moved from the R&D department to ASTRON staff level and will be combined with the other business development activities of ASTRON.

- The R&D secretariat will be organized as a Competence Group with its own line manager.

- The scientific staff will be integrated in the competence groups.

- Some areas and processes will be organized department wide (like acquisition of projects, architecture, and research) involving people from all competence groups.

As a result of the aforementioned and also related to the optimization of the matching of expertise within the groups, a number of R&D employees will be reallocated to a new or another Competence Group.

The coming weeks/months this new overall R&D structure will be implemented.

We are aware that these changes will take time and effort of not only the colleagues who will move to another group but of all the R&D employees.

Based on the positive reactions we are confident that we can do this together!


The marvel of low-tech

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©

What's the best way of tracking progress and while doing so, motivating your team? This question has been raised several times in the APERTIF room. And now, thanks to Marcel, we have the ultimate solution!

In the dynamic development environment of APERTIF we need a flexible issue tracker and progress monitoring tool. We use Redmine for this purpose and while it serves us well, if you don't look actively at it you don't know what the status of the project is.

(OK, we could keep our nice big TV screen turned on the whole day and our Redmine task list displayed there. However, such a suggestion does not go down well when you have two thirds of the ASTRON Sustainability Committee sitting in the APERTIF room.)

So what we did was rescue a lonely whiteboard, get some insulation tape and sticky notes in as many colours as we could find and voila! We are proud to present our "scrum board" which is on continuous display in the APERTIF room, does not consume an ounce of energy and is more colourful than Redmine could ever dream of.

Joint effort in the construction of a Meccanoid XL personal robot 2.0

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© R&D

As already mentioned in one of the previous daily images, since September last year we are official member of the Innovation Cluster Drachten (ICD, high tech materials). To welcome us, the president gave us a very nice present: a Meccanoid XL personal robot 2.0. This robot is the size of a 10 - 11 years old child (around 1.40 m), is provided with enhanced voice recognition, and communicates with smart devices by Bluetooth wireless technology with a free app for Android and iOS. However, this robot consisted of 1020 parts and had to be built and programmed by ourselves.

A few months ago, the people of the R&D department have been encouraged to submit an idea for the construction of this Meccanoid XL personal robot 2.0. Bas van der Tol, Andre Gunst and Arthur Coolen of the R&D department and Jeremy Hartwood and Andre Offringa of the Astronomy Group, together with their children in the age of 10 - 13, submitted the winning idea: to program the robot as a.o. greeter/host/guide for ASTRON open days and visitor tours.

Last week, the team enthusiastically started with this challenge. Building the robot appeared to be a really good team effort. The kids (and adults) collaborated effectively. A lot of the work was done in parallel, such that the mechanical building of the robot could be finished within an afternoon. Furthermore, the kids had a lot of fun as well and are eagerly waiting for the next phase: programming the robot. This will be planned soon.

We will keep you informed on the final result!

...placeholder AJDI Jason Hessels ... (unaccept, don't delete!)

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© MCC

For upcoming ASTRON/JIVE colloqiua, click here

A New Year, a renewed Mechanical Group at ASTRON R&D department

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© Johan Pragt / Annemieke Janssen

The Mechanical Group is partially renewed and back on full strength now. The group consists of two different disciplines: Mechanical R&D and Prototyping Group ('Instrumentmakerij'). They are complementary to each other and working great together.

In the picture you see from the left to the right:

  • Jorrit Siebenga, 'instrumentmaker' with experience at some companies and educated at the well known LIS (Leidse Instrument Makers School, the best MBO of the Netherlands).

  • Jeroen Herrewijnen, more than ten years of experience in mass production at Philips and also several years of experience in machine building, design and analysis at several companies.

  • Sjouke Kuindersma, our experienced 'instrumentmaker' with about eighteen years of experience at ASTRON in all required techniques. Sjouke also has a background at the LIS.

  • Paula Fusiara, a few years now at ASTRON and full of ambition for new developments and techniques for the next steps in Mechanical Design.

  • Johan Pragt, leading the Mechanical Group since 2000 and looking forward to the future of new developments in Mechanical R&D and production of prototypes with this new group.

    As Mechanical Group we cover a broad spectrum of Mechanics: From Research and Development up to realization of prototyping and production tooling. Keywords: Brainstorm, Mass production, Antennas, Analysis, Electronics, Low cost, plastic-metal combinations, 3D printing, HPC thermal design, CNC milling, vacuum, cryogenic, and more...

    We cover the Electro Magnetic wavelength range from meters to microns.

    What happened with our former colleagues of the Mechanical Group?

  • Marco Drost is promoted to the Radio Observatory.

  • Raymond van den Brink is now working at Tricas in Zwolle as project manager and developer.

  • Hiddo Hanenburg and Jan Idserda both retired recently.
  • Improving pipeline description methods, take 2

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    © -

    As already advertised last month, the Prefactor calibration pipeline has been ported to the Common Workflow Language (CWL). During the project meet-up on 8 January, Gijs Molenaar presented the result of his work in the EOSC pilot for LOFAR, that he did in collaboration with Michael Crusoe.

    CWL in combination with container technology like Singularity, Docker or uDocker makes it easy to deploy pipelines on different platforms. The pipeline description itself is container technology agnostic. Indeed, Gijs tested the Prefactor pipeline on SurfSara's Cartesius, and yours truly verified during the presentation that installing and running the pipeline on a laptop can be done while listening to a presentation.

    Advantages of formalising pipelines in a standard language like CWL, as opposed to say Makefiles or python scripts, are that the pipeline becomes more portable and scalable across different compute environments. Also, by describing the pipeline and tools involved in a formal way, a pipeline management package can work out dependencies between steps, and run several steps in parallel. Lastly, it makes it easy to develop pipelines in a graphical, understandable way.

    The image above was automatically parsed from the Prefactor CWL description using Rabix Composer, and brushed up a bit in Inkscape.

    CWL pipelines can be run with several workflow engines. One of them is TOIL, a tool more often used in Genomics. This engine can export SLURM jobs, which makes it a nice candidate to run on CEP3, which is being worked on.

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