Previous LOFAR newsletters are collected here. 

Published by the editorial team, 19 January 2024



    LOFAR Data School 2024

    The 7th LOFAR Data School will be held at ASTRON in Dwingeloo during April 15 - 19, 2024. Registration is now closed.

    Below is a summary of important dates and future deadlines:

    • February 1st 2024: deadline to pay registration fee. All confirmed participants should pay the fee before the deadline
    • February 2024: confirmed participants should make their own accommodation reservations before February 1st, 2024
    • April 14th: arrival in Dwingeloo for the 7th LOFAR Data School
    • 15 - 19 April: 7th LOFAR Data School

    Please visit the official website of the school for more details. If you have any question(s) or need further clarification, you may contact the LOC via

    Data staging and downloading from the LTA sites

    Data staging and downloads from the LTA sites were stable in the past months, except during the few maintenance days over which the services were unavailable. Planned maintenance days are always mentioned on the LTA portal. Contact SDC-Helpdesk if experiencing any issues with staging and downloads.

    The Dutch (SURF) and German (Jülich) LOFAR LTA data centers are ready to support more performant and reliable data access, offering a.o. WEBDAV and token based authorization. The Polish (Poznan) data center has been making progress upgrading their environment to support this as well. Once all centers are ready, we will offer the new access methods through an upgraded stager service called 'StageIt' which has been developed by the SDC software development team. StageIt itself provides enhanced functionality for automated and interactive user staging requests. Details and instructions will be distributed as soon as the required functionality is in place.

    COBALT node down

    From December 28th, 2023 to January 2nd, 2024 one of the Cobalt correlator nodes was out of service. Hence, LOFAR was offline and no observations were performed during this period.

    Array and observing system status

    LOFAR map

    • 38 stations operational in the Netherlands: 24 core and 14 remote stations. 14 international stations in operations: DE601, DE602, DE603, DE604, DE605, FR606, SE607, UK608, DE609, PL610, PL611, PL612, IE613, LV614.
    • New international stations will be built in Italy and Bulgaria in the coming years. Both stations will be equipped with LOFAR2.0 hardware, whose installation/rollout is expected in 2025.
    • Antenna elements of all stations are performing nominally, except CS005, CS103 and RS503 HBA, and RS210 LBA that have between 16 and 23% % non-operational elements. Those elements are either broken to be fixed or broken beyond repair. The overview of non-operational antenna elements for LBA and HBA is available here. At the stations level, all stations are online, at least for most part of the period under consideration, except DE601 which had broken RSPDriver and has been down for some months now. The issue with DE601 is linked to the flooding that happened some months ago. Engineers from ASTRON will visit the station to help resolve the problem as soon as possible.
    • Moreover, no major failures occurred on CEP hardware/software over the past couple of months. A major upgrade of the processing cluster is planned to happen later this year or early next year.

    Observing programs

    • Cycle 20 observing campaign started on 1 June 2023 and will run till 31 May 2024. The public version of the observing schedule in TMSS will be available in due course. For now, only PIs can see their projects in TMSS.
    • At the end of the first seven and a half months of observations (till January 14, 2024), we have done about 4170 hours of production observations. This translates into observing efficiency of 77% and the completion level of 74%.



    Telescope Manager Specification System (TMSS; A. Schoenmakers, S. ter Veen)

    • We are closing the first quarterly planning increment (PI-1) that started on October 23rd, 2023. One of the goals of this increment was to deliver all necessary functionality to conclude the current LOFAR Cycle 20. This includes yet to be used observing modes, the Quality Assessment workflow, the creation of reports on project and cycle progress and failures, improved usability, day and week views, and many other user interface enhancements. Close cooperation between team Ruby, Operators and SDCO staff ensured that the interface has become much more mature, responsive, and usable.
    • In addition, the team has finetuned the dynamic scheduling algorithm and the plots representing the outcome of the scheduling process in TMSS. For example, a constraint has been added to not allow a calibrator source to be observed when it is close to a bright source such as the Sun or Jupiter.- In the coming period the focus will be shifted to preparations for LOFAR2.0. For instance, LOFAR2.0 specific specification and scheduling constraints will be needed once the LOFAR2.0 development team will roll out more test stations. Furthermore, automation of station validation and verification observations will accelerate these processes and make these much easier to repeat.


    Screenshot of TMSS QA workflow view
    Figure 1. TMSS QA workflow view


    LOFAR Development program (W. van Cappellen)

    • The verification of the LOFAR2.0 design in the test station (CS001) was successfully completed and the hardware design has been released for production.
    • LOFAR2.0 final hardware production has started. CS001 continues to operate as a test station and in March/April 2024 two more stations (CS032 and RS307) will be upgraded to LOFAR2.0 as well. These stations serve as "production test stations" to verify that all production processes deliver as expected. After this brief verification period the production is continued to provide hardware for all other stations. Installation is planned from early 2025.
    • The rollout of the Timing Distributor has commenced. Currently, four stations have been upgraded (CS001, RS307, RS207, and RS205). This number steadily increases. Verification observations demonstrate that the clock/timing accuracy of the upgraded stations is now well within 1 ns over a period of 8 hours. This is a huge improvement compared to the old situation where clock drifts of 10-20 ns were common.
    • The network switch to upgrade the core network in Groningen has been ordered. It will form the heart of the new network backbone and brings us a step closer to the ambition to connect all stations to 100 Gbit/s in the future! The new network will be installed in parallel to the old one. When stations are upgraded to LOFAR2.0 they are moved from the old to the new network. Also, CEP6 and COBALT3 will be connected to the new network. When the new system is fully up and running the old network equipment is removed.
    • First light of the new HBA electronics was achieved on 10 October when a full HBA tile of L2TS (CS001) was upgraded with the frontends delivered by the DANTE project. The new HBA electronics will be installed in the new LOFAR stations in Italy and Bulgaria.


    SDC program (J. Swinbank)

    • Following the successful release of the Rapthor [1] direction-dependent calibration & imaging pipeline in June 2023, the team is now focused on:
      • Support for LBA processing in the LINC (direction-independent) pipeline.
      • A VLBI “postage stamp” pipeline based on the same framework used in LINC [2] and Rapthor.
      • A series of performance improvements to Rapthor, as well as a benchmarking suite to help us monitor the evolution of Rapthor's performance with time.
    • We hope to make versions of all of these available early in 2024, although as pre-releases only in some cases.


    • The SDC pipeline execution system has now been demonstrated to support at-scale in the context of the LDV project. We are continuing to iterate and improve on this system, with upcoming goals including extension to support processing across all LTA sites. In the long term, we expect this to form the basis of processing LOFAR2.0 data.
    • The SDC has recently added a UX designer to our team, and they are working on improving the usability and consistency of the web services we provide to LOFAR users. While of course we're looking forward to giving everything a fresh modern look, the real value here is in making sure we adopt best practices for accessibility (e.g. WCAG [3]) so that everybody can benefit from LOFAR data. An example of some of the work in progress is shown in the attached image.


    Image showing ASTRON SDC UI theme proposal
    Figure 2. ASTRON SDC UI theme proposal


    • The old LOFAR proposal tool - Northstar - will be replaced before LOFAR2.0 enters operations. The new system will be both more flexible to enable advanced observing modes, and easier for the ASTRON team to develop and maintain. And, of course, it will build on the new web design system! The new system will be based on Hedwig [4], developed at the East Asian Observatory, and will be the focus of much of our development effort over the next several months. We look forward to sharing more details as we go![4]
    • The next couple of years will be an exciting time, as we prepare for, commission, and being operating LOFAR2.0. The SDC development team is excited to work together with the wider community to maximise the scientific output for everybody. Look out for more opportunities to get involved soon, and please don't hesitate to share your feedback — reach out to with your ideas.

    Calendar of upcoming LOFAR activities

    The dates of LOFAR Status Meetings, roll-outs and stop days are listed in an online calendar that is available here.


    SDC Helpdesk