Dario Dorigo

Quality control systems for the Very Large Telescope

The operational applications needed to quantitatively assess VLT calibration and science data are provided by the VLT Quality Control system (QC). In the Data Flow observation life-cycle, QC relates data pipeline processing and observation preparation. It allows the ESO Quality Control Scientists of the Data Flow Operations group to populate and maintain the pipeline calibration database, to measure and verify the quality of observations, and to follow instrument trends. The QC system also includes models allowing users to predict instrument performance, and the Exposure Time Calculators are probably the QC applications most visible to the astronomical community. The Quality Control system is designed to cope with the large data volumes of the VLT, the geographical distribution of data handling, and the parallelism of observations executed on the different unit telescopes and instruments.

New observing concepts for ESO survey telescopes

The start of operations of the VISTA survey telescope will not only offer a new facility to the ESO community, but also a new way of observing. Survey observation programs typically observe large areas of the sky and might span several years, corresponding to the execution of hundreds of observations blocks (OBs) in service mode. However, the execution time of an individual survey OB will often be rather short. We expect that up to twelve OBs may be executed per hour, as opposed to about one OB per hour on ESOs Very Large Telescope (VLT). OBs of different programs are competing for observation time and must be executed with adequate priority. For these reasons, the scheduling of survey OBs is required to be almost fully automated. Two new key concepts are introduced to address these challenges: ESOs phase 2 proposal preparation tool P2PP allows PIs of survey programs to express advanced mid-term observing strategies using scheduling containers of OBs (groups, timelinks, concatenations). Telescope operators are provided with effective short-term decision support based on ranking observable OBs. The ranking takes into account both empirical probability distributions of various constraints and the observing strategy described by the scheduling containers. We introduce the three scheduling container types and describe how survey OBs are ranked. We demonstrate how the new concepts are implemented in the preparation and observing tools and give an overview of the end-to-end workflow.

Evolution of the phase 2 preparation and observation tools at ESO

Throughout the course of many years of observations at the VLT, the phase 2 software applications supporting the specification, execution and reporting of observations have been continuously improved and refined. Specifically the introduction of astronomical surveys propelled the creation of new tools to express more sophisticated, longer-term observing strategies often consisting of several hundreds of observations. During the execution phase, such survey programs compete with other service and visitor mode observations and a number of constraints have to be considered. In order to maximize telescope utilization and execute all programs in a fair way, new algorithms have been developed to prioritize observable OBs taking into account both current and future constraints (e.g. OB time constraints, technical telescope time) and suggest the next OB to be executed. As a side effect, a higher degree of observation automation enables operators to run telescopes mostly autonomously with little supervision by a support astronomer. We describe the new tools that have been deployed and the iterative and incremental software development process applied to develop them. We present our key software technologies used so far and discuss potential future evolution both in terms of features as well as software technologies.

Moor: web access to end-to-end data flow information at ESO

All ESO Science Operations teams operate on Observing Runs, loosely defined as blocks of observing time on a specific instrument. Observing Runs are submitted as part of an Observing Proposal and executed in Service or Visitor Mode. As an Observing Run progresses through its life-cycle, more and more information gets associated to it: Referee reports, feasibility and technical evaluations, constraints, pre-observation data, science and calibration frames, etc. The Manager of Observing Runs project (Moor) will develop a system to collect operational information in a database, offer integrated access to information stored in several independent databases, and allow HTML-based navigation over the whole information set. Some Moor services are also offered as extensions to, or complemented by, existing desktop applications.

The ESO astronomical site monitor upgrade

Monitoring and prediction of astronomical observing conditions are essential for planning and optimizing observations. For this purpose, ESO, in the 90s, developed the concept of an Astronomical Site Monitor (ASM), as a facility fully integrated in the operations of the VLT observatory[1]. Identical systems were installed at Paranal and La Silla, providing comprehensive local weather information. By now, we had very good reasons for a major upgrade: • The need of introducing new features to satisfy the requirements of observing with the Adaptive Optics Facility and to benefit other Adaptive Optics systems. • Managing hardware and software obsolescence. • Making the system more maintainable and expandable by integrating off-the-shelf hardware solutions. The new ASM integrates: • A new Differential Image Motion Monitor (DIMM) paired with a Multi Aperture Scintillation Sensor (MASS) to measure the vertical distribution of turbulence in the high atmosphere and its characteristic velocity. • A new SLOpe Detection And Ranging (SLODAR) telescope, for measuring the altitude and intensity of turbulent layers in the low atmosphere. • A water vapour radiometer to monitor the water vapour content of the atmosphere. • The old weather tower, which is being refurbished with new sensors. The telescopes and the devices integrated are commercial products and we have used as much as possible the control system from the vendors. The existing external interfaces, based on the VLT standards, have been maintained for full backward compatibility. All data produced by the system are directly fed in real time into a relational database. A completely new web-based display replaces the obsolete plots based on HP-UX RTAP. We analyse here the architectural and technological choices and discuss the motivations and trade-offs.