After 20 years of operations, the Paranal Observatory has accumulated some experience with maintenance of systems, and has lately adopted the methodology called ‘Maintien en Condition Operationnelle’ (MCO). We will describe and review the practical implementation of this strategy, the tools used, the benefits and challenges as well as practical examples and how it is overall managed. The approach is also a benchmarking exercise for operation of the ESO-ELT in the future.
For almost two decades, large volumes of technical data, in a variety of formats, have resulted from the normal operations at the observatory. Similarly, in the last few years, dealing with huge amounts of data has become a priority for several industries, and as consequence, terms like "Big Data" or "Data Lake" have started to be more and more commonly used. Under these circumstances, frameworks and tools have proliferated and later released as "Open Software"; the hardware, on the other hand, has also changed giving the power to deal with this volume of data in a reasonable timeframe, and at a reasonable price. <p> </p>We hereafter present the first version of a modern data lab developed for the Maintenance Support and Engineering Department (MSE) at the Paranal Observatory, “The MSE DataLab”. This DataLab will allow us to take advantage of this new technological evolution and to be prepared for the current and further challenges to come. These challenges, of course, refer to improving the overall observatory dependability (Reliability, Availability and Maintainability) by supporting the operations in our current and forthcoming telescopes. First, in our Very Large Telescopes (VLT), the VLT Interferometer (VLTI) and the survey telescopes (VISTA and VST). Secondly, in the Extremely Large Telescope (ELT) and the Cherenkov Telescope Array (CTA).
MATISSE (Multi AperTure mid-Infrared SpectroScopic Experiment) is the spectro-interferometer for the VLTI of the European Southern Observatory (ESO), operating in the L-, M- and N- spectral bands, and combining up to four beams from the unit or the auxiliary telescopes (UTs or ATs). MATISSE will offer new breakthroughs in the study of circumstellar environments by allowing the mapping of the material distribution, the gas and essentially the dust. The instrument consists in a warm optical system (WOP) accepting four beams from the VLTI and relaying them after a spectral splitting to cold optical benches (COB) located in two separate cryostats, one in L-M- band, and one in N-band. The test plan of the complete instrument has been conducted at the Observatoire de la Côte d’Azur in order to confirm the compliance of the performance with the high-level requirements. MATISSE has successfully passed the Preliminary Acceptance in Europe the 12th September 2017. Following this result, ESO gave approval for the instrument to be shipped to Paranal. The Alignment, Integration and Verification phase was conducted until end of February 2018, at the end of which first observations on sky have been performed to test the operations with the VLTI and to obtain first stellar light. The two first runs of the commissioning followed, respectively in March and in May 2018. It has the goal to optimize the MATISSE-VLTI communication, the acquisition procedures and the interface parameters. The observations were performed on bright L-M- and N- stars, with four ATs located on short baselines and UTs. The limit magnitudes will be deduced.<p> </p> This paper reports on the performance of the instrument measured in laboratory (results of test plan in Nice and AIV in Paranal) in terms of spectral coverage, dispersion laws and spectral resolutions, and transfer function analysis: instrumental contrast, visibility accuracy, accuracy of the differential phase, of the closure-phase and of the differential visibility. It also provides results of the first tests on sky and the planning of the on-going commissioning.
The near-infrared GRAVITY instrument has become a fully operational spectro-imager, while expanding its capability to support astrometry of the key Galactic Centre science. The mid-infrared MATISSE instrument has just arrived on Paranal and is starting its commissioning phase. NAOMI, the new adaptive optics for the Auxiliary Telescopes, is about to leave Europe for an installation in the fall of 2018. Meanwhile, the interferometer infrastructure has continuously improved in performance, in term of transmission and vibrations, when used with both the Unit Telescopes and Auxiliary Telescopes. These are the highlights of the last two years of the VLTI 2nd generation upgrade started in 2015.
The New Adaptive Optics Module for Interferometry (NAOMI) is ready to be installed at the 1.8-metre Auxiliary Telescopes (ATs) at ESO Paranal. NAOMI will make the existing interferometer performance less dependent on the seeing conditions. Fed with higher and more stable Strehl, the fringe tracker will achieve the fringe stability necessary to reach the full performance of the second-generation instruments GRAVITY and MATISSE. All four ATs will be equipped between September and November 2018 with a Deformable mirror (ALPAO DM-241), a 4*4 Shack– Hartmann adaptive optics system operating in the visible and an RTC based on SPARTA Light. During the last 6 months thorough system test has been made in laboratory to demonstrate the Adaptive Optics and chopping capability of NAOMI.
ESO is undertaking a large upgrade of the infrastructure on Cerro Paranal in order to integrate the 2nd generation of interferometric instruments Gravity and MATISSE, and increase its performance. This upgrade started mid 2014 with the construction of a service station for the Auxiliary Telescopes and will end with the implementation of the adaptive optics system for the Auxiliary telescope (NAOMI) in 2018. This upgrade has an impact on the infrastructure of the VLTI, as well as its sub-systems and scientific instruments.
For large telescopes, like the Very Large Telescope (VLT) unit telescopes, it is compulsory to use an effective and reliable Active Optics system in order to guarantee the optimal optical performance. The active optics ensures that the actual wavefront aberrations introduced by the telescope itself are kept as low as possible. In order to evaluate the longterm performance of this system, an extended timeseries data analysis for all four unit telescopes (UT) was performed. The results presented in this paper demonstrate that the VLT UT active optics system works very stable and reliable with no significant performance degradation over time.
The Paranal Very Large Telescopes (VLT) Observatory is a complex multifunctional observatory where many different systems are generating telemetry parameters.As systems becoming more and more complex, also the amount of telemetry data is increasing. This telemetry data is usually saved in various data repositories.In order to obtain a full system overview, it is necessary to link all that data in a meaningful and easy to interpret way. A step forward from simple telemetry data visualisation has been done by developing a new tool that can combine different data sources and has a powerful graphing capability.This new tool, called SystMon, is developed in iPython an interactive-web browser environment under the philosophy of notebooks which combine the code and the final product. The application can be shared among other colleagues and having the code side by side gives the accessibility to inspect and review the process improving and adding new capabilities to the application. SystMon allows to manipulate, generate andvisualise data in different types of graphs and also to create directly statistical reports. SystMon helps the user tomodel, visualiseand interpret telemetry data in a web-based platform for monitoring the health of systems, understanding short- and long-term behaviour and to anticipate corrective interventions.