The instrumentation of the Prime Focus Spectrograph (PFS), a next generation facility instrument on the Subaru telescope, is now in the final phase of its commissioning process and its general, open-use operations for sciences will provisionally start in 2025. The instrument enables simultaneous spectroscopy with 2386 individual fibers distributed over a very wide (∼1.3 degrees in diameter) field of view on the Subaru’s prime focus. The spectra cover a wide range of wavelengths from 380nm to 1260nm in one exposure in the Low-Resolution (LR) mode (while the visible red channel has the Medium-Resolution (MR) mode as well that covers 710−885nm). The system integration activities at the observatory on Maunakea in Hawaii have been continuing since the arrival of the Metrology Camera System in 2018. On-sky engineering tests and observations have also been carried out continually since September 2021 and, despite various difficulties in interlacing commissioning processes with development activities on the schedule and addressing some major issues on hardware and software, the team successfully observed many targeted stars as intended over the entire field of view (Engineering First Light) in September 2022. Then in parallel to the arrival, integration and commissioning of more hardware components, validations and optimizations of the performance and operation of the instrument are ongoing. The accuracy of the fiber positioning process and the speed of the fiber reconfiguration process have been recently confirmed to be ∼ 20−30μm for 95% of allocated fibers, and ∼130 seconds, respectively. While precise quantitative analyses are still in progress, the measured throughput has been confirmed to be consistent with the model where the information from various sub-components and sub-assemblies is integrated. Long integration of relatively faint objects are being taken to validate an expected increase of signal-to-noise ratio as more exposures are taken and co-added without any serious systematic errors from, e.g., sky subtraction process. The PFS science operation will be carried out in a queue mode by default and various developments, implementations and validations have been underway accordingly in parallel to the instrument commissioning activities. Meetings and sessions are arranged continually with the communities of potential PFS users on multiple scales, and discussions are iterated for mutual understanding and possible optimization of the rules and procedures over a wide range of processes such as proposal submission, observation planning, data acquisition and data delivery. The end-to-end processes of queue observations including successive exposures with updated plans based on assessed qualities of the data from past observations are being tested during engineering observations, and further optimizations are being undertaken. In this contribution, a top-level summary of these achievements and ongoing progresses and future perspectives will be provided.
We present a simple sytem for job distribution built on the RabbitMQ open-source message broker. The system is based on the concept of job sources (origins), sinks (destinations) and realms (hubs), where a network of these entities can be readily established with a configuration file for each site and a RabbitMQ server running at each hub. Jobs are sent via persistent JSON-encoded packets and delivered reliably by RabbitMQ queues. The system was built primarily for robust data tranfers amidst volatile network connections but is general enough for any kind of flexible job distribution scheme where reliable delivery of job messages is needed. We are releasing the ”datasink” as an open-source Python package on Github. Aside from RabbitMQ, there are minimal additional requirements.
Prime Focus Spectrograph (PFS) is a next generation instrument mounted on the Subaru telescope. It is a fiber-fed multiplex system covering a wide field of view (1.3 degree in diameter), which enables to acquire approximately 2400 spectra of science objects simultaneously. In order to efficiently use fibers, open-use programs will share fibers with each other (the fiber-sharing mode). Here, we introduce the PFS Pointing Planner (PPP), the tool to optimize the pointing centers. Its goal is to efficiently observe all allocated time of science programs while assigning as many fibers as possible to science targets on each pointing. The tool incorporates a flexible weight scheme which considers factors such as the science priority, surface density and exposure time. We present the simulation results of PPP with mock science programs, and discuss its performance in diverse science cases.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is now being tested on the telescope. The instrument is equipped with very wide (1.3 degrees in diameter) field of view on the Subaru’s prime focus, high multiplexity by 2394 reconfigurable fibers, and wide waveband spectrograph that covers from 380nm to 1260nm simultaneously in one exposure. Currently engineering observations are ongoing with Prime Focus Instrument (PFI), Metrology Camera System (MCS), the first spectrpgraph module (SM1) with visible cameras and the first fiber cable providing optical link between PFI and SM1. Among the rest of the hardware, the second fiber cable has been already installed on the telescope and in the dome building since April 2022, and the two others were also delivered in June 2022. The integration and test of next SMs including near-infrared cameras are ongoing for timely deliveries. The progress in the software development is also worth noting. The instrument control software delivered with the subsystems is being well integrated with its system-level layer, the telescope system, observation planning software and associated databases. The data reduction pipelines are also rapidly progressing especially since sky spectra started being taken in early 2021 using Subaru Nigh Sky Spectrograph (SuNSS), and more recently using PFI during the engineering observations. In parallel to these instrumentation activities, the PFS science team in the collaboration is timely formulating a plan of large-sky survey observation to be proposed and conducted as a Subaru Strategic Program (SSP) from 2024. In this article, we report these recent progresses, ongoing developments and future perspectives of the PFS instrumentation.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is a very wide- field, massively multiplexed, and optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed in the 1.3 degree-diameter field of view. The spectrograph system has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously deliver spectra from 380nm to 1260nm in one exposure. The instrumentation has been conducted by the international collaboration managed by the project office hosted by Kavli IPMU. The team is actively integrating and testing the hardware and software of the subsystems some of which such as Metrology Camera System, the first Spectrograph Module, and the first on-telescope fiber cable have been delivered to the Subaru telescope observatory at the summit of Maunakea since 2018. The development is progressing in order to start on-sky engineering observation in 2021, and science operation in 2023. In parallel, the collaboration is trying to timely develop a plan of large-sky survey observation to be proposed and conducted in the framework of Subaru Strategic Program (SSP). This article gives an overview of the recent progress, current status and future perspectives of the instrumentation and scientific operation.
Subaru Telescope, an 8meter class optical telescope located in Hawaii, has been using a high availability commodity cluster as a platform for our Observation Control System for many years.1 A concerted attempt to virtualize this infrastructure using conventional virtual machines2 was eventually scuttled due to performance impacts on the observation software under sustained use. With the ascendance of container-based virtualization, and its promise of high-efficiency, we recently attempted this effort anew, and have found success with an approach that employs Linux (LXC) containers. This has provided immediate benefits in maintenance, risk management and availability. In this paper, we document our transition and discuss the rationale for this choice vs. the arguably more popular Docker containerization scheme. We list some of the issues we encountered and solved to realize a successful transition to containers. We have also recently converted our software stack to being based on Miniconda, a popular, opensource, crossplatform software distribution service. This move basically decoupled our software completely from the operating system platform, and provides a virtualized software stack with many desirable benefits. The combination of the LXC containers and Miniconda gives us an orthogonal three-axis virtualization scheme with extreme flexibility. We present our system for managing Miniconda environments, the benefits that accrue, and how this three-axis approach to virtualization has altered our deployment and management strategies.
The Subaru Telescope recently celebrated its 20th year of operation. Despite that lengthy period of successful operation, it has never had a proper simulator for its telescope control system. This fact complicates the development and testing of observing scripts that need to send commands and receive realistic feedback from both telescope and instrument systems. The Subaru telescope control system was developed by a subcontractor and there was no requirement for it to be able to run in simulation mode. Furthermore, the source code is proprietary and is not accessible by current Subaru software engineers. These two facts greatly complicated the development of a telescope simulator. Prior to the current effort, the telescope simulator consisted of a “yes-man” interface, i.e., the rudimentary simulator would just respond that it received the command but would not simulate telescope motion or set any status items to provide feedback to the observing scripts. The telescope simulator developed in this effort currently simulates the following components: telescope and instrument rotator motion, focal station configuration, autoguide camera images and pointing errors, as well as facility hardware like dome shutters and mirror covers. We have plans to further refine all those components and implement features like simulated environmental conditions based on historical weather data. The simulator has already proven useful in testing observation scripts. In addition, the simulator will also be a good training aid for new telescope operators.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~ 1.6-2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project recently started undertaking the commissioning process of a subsystem at the Subaru Telescope side, with the integration and test processes of the other subsystems ongoing in parallel. We are aiming to start engineering night-sky operations in 2019, and observations for scientific use in 2021. This article gives an overview of the instrument, current project status and future paths forward.
Subaru Telescope, an 8-meter class optical telescope located in Hawaii, has been using a high-availability commodity cluster as a platform for our Observation Control System (OCS). Until recently, we have followed a tried-and-tested practice of running the system under a native (Linux) OS installation with dedicated attached RAID systems and following a strict cluster deployment model to facilitate failover handling of hardware problems,1.2 Following the apparent benefits of virtualizing (i.e. running in Virtual Machines (VMs)) many of the non- observation critical systems at the base facility, we recently began to explore the idea of migrating other parts of the observatory's computing infrastructure to virtualized systems, including the summit OCS, data analysis systems and even the front ends of various Instrument Control Systems. In this paper we describe our experience with the initial migration of the Observation Control System to virtual machines running on the cluster and using a new generation tool – ansible - to automate installation and deployment. This change has significant impacts for ease of cluster maintenance, upgrades, snapshots/backups, risk-management, availability, performance, cost-savings and energy use. In this paper we discuss some of the trade-offs involved in this virtualization and some of the impacts for the above-mentioned areas, as well as the specific techniques we are using to accomplish the changeover, simplify installation and reduce management complexity.
The astronomical community has a long tradition of sharing and collaborating on FITS file tools, including viewers. Several excellent viewers such as DS9 and Skycat have been successfully reused again and again. Yet this "first generation" of viewers predate the emergence of a new class of powerful object-oriented scripting languages such as Python, which has quickly become a very popular language for astronomical (and general scientific) use. Integration and extension of these viewers by Python is cumbersome. Furthermore, these viewers are also built on older widget toolkits such as Tcl/Tk, which are becoming increasingly difficult to support and extend as time passes.
Suburu Telescope's second-generation observation control system (Gen2) is built on a a foundation of Python-based technologies and leverages several important astronomically useful packages such as numpy and pyfits. We have written a new flexible core widget for viewing FITS files which is available in versions for both the modern Gtk and Qt-based desktops. The widget offers seamless integration with pyfits and numpy arrays of FITS data. A full-featured viewer based on this widget has been developed, and supports a plug-in architecture in which new features can be added by scripting simple Python modules. In this paper we will describe and demonstrate the capabilities of the new widget and viewer and discuss the architecture of the software which allows new features and widgets to easily developed by subclassing a powerful abstract base class. The software will be released as open-source.
We introduce the detail of the control system of Hyper Suprime-Cam (HSC) and its performance. Although it
has almost 10 times as many CCDs (104) as existing camera (Suprime-Cam), it is controlled by the common
user interface, the Subaru Observation Software System (SOSS) with the Gen2 implementation through the
HSC local controller (OBCP). If we adopt parallel programming, the read-out time should be within 25 seconds
including 18.6 seconds of readout time which is comparable to the current Suprime-Cam.
Subaru Telescope is deploying and commissioning a second-generation
Observation Control System (OCS), building upon a 10 hear history of
using the first generation OCS, and seeking to improve several key
aspects of managing and using it. Replacing an extensive, functional,
mission-critical software at the core of the telescope is an ambitious
undertaking. In this paper we present some important and sometimes
surprising lessons learned during the buildout and commissioning phase
of the Generation 2 OCS at Subaru Telescope. We present our experience
with the rewrite vs. refactor decision, aspects of testing including
unit and functional tests, compatibility decisions regarding legacy
systems, and managing telescope priorities vs. developer priorities.
KEYWORDS: Control systems design, Telescopes, Optical instrument design, Data backup, Distributed computing, Failure analysis, Astronomy, Current controlled current source, Databases, Clouds
Subaru Telescope is commissioning a second-generation Observation
Control System (OCS), building upon a 10 hear history of using the first generation OCS. One of the primary lessons learned about maintaining a distributed OCS system is that the idea of individual computer nodes specialized for specific functions greatly complicates troubleshooting and failover, even with a dedicated "hot spare" for each specialized node.
In contrast, the Generation 2 (Gen2) system was designed from the ground up around the principle of a High-Availability (HA) cluster, commonly used for high-traffic, mission-critical web sites. In such a cluster, nodes are not specialized, and any node can perform any function of the OCS. We describe the problems encountered in trying to troubleshoot and manage failure on the legacy OCS system and describe the architectural design of the HA cluster for the new system, including special characteristics designed for the high-altitude, remote environment of the summit of Mauna Kea, where there is a greatly increased probability of such failures. Although the focus is primarily on the hardware, we touch upon the software architecture written to take advantage of the features of the HA cluster design. Finally, we outline the advantages of the new system and show how the design greatly facilitates troubleshooting, robustness and ease of failure management. The results
may be of interest to anyone designing a distributed system using COTS
hardware and open-source software to withstand failure and improve
manageability in a remote environment.
The Fibre Multi-Object Spectrograph for Subaru Telescope (FMOS) is a near-infrared instrument with 400
fibres in a 30' filed of view at F/2 prime focus. To observe 400 objects simultaneously, we have developed a fibre
positioner called "Echidna" using a tube piezo actuator. We have also developed two OH-airglow suppressed and
refrigerated spectrographs. Each spectrograph has two spectral resolution modes: the low-resolution mode and
the high-resolution mode. The low-resolution mode covers the complete wavelength range of 0.9 - 1.8 μm with
one exposure, while the high-resolution mode requires four exposures at different camera positions to cover the
full wavelength range. The first light was accomplished in May 2008. The science observations and the open-use
observations begin in May 2010.
KEYWORDS: Control systems design, Telescopes, Optical instrument design, Astronomy, Computer programming, Control systems, Scientific programming, Observatories, Computer programming languages
Subaru Telescope is developing a second-generation Observation Control System that specifically addresses some of the deficiencies of the current Subaru OCS. One area of concern is better extensibility: the current system uses a custom language for implementing commands with a complex macro processing subsystem written in C. It is laborious to improve the language and awkward for scientists to extend and use standard programming techniques.
Our Generation 2 OCS provides a lightweight, object-oriented task framework based on the Command design pattern. The framework provides a base task class that abstracts services for processing status and other common infrastructure activities. Upon this are built and provided a set of "atomic" tasks for telescope and instrument commands. A set of "container" tasks based on common sequential and concurrent command processing paradigms is also included. Since all tasks share the same exact interface, it is straightforward to build up compound tasks by plugging simple tasks into container tasks and container tasks into other containers, and so forth. In this way various advanced astronomical workflows can be readily created, with well controlled behaviors. In addition, since tasks are written in Python, it is easy for astronomers to subclass and extend the standard observatory tasks with their own custom extensions and behaviors, in a high-level, full-featured programming language. In this talk we will provide an overview of the task framework design and present preliminary results on the use of the framework during two separate engineering runs.
Subaru Telescope is developing a second-generation Observation Control
System that specifically addresses some of the deficiencies of the
current Subaru OCS. Two areas of concern are complexity and failure
handling. The current system has over 1000 dedicated OCS
processes spread across a dozen hosts and provides nothing in the
way of automated failover. Furthermore, manual failover is so fraught
with difficulty that it is rarely attempted.
Our Generation 2 OCS is written almost entirely in Python and builds
upon a Subaru-developed middleware based on the XML-RPC protocol.
This framework offers the following benefits:
- has very few dependences outside of standard Python
- provides a nearly seamless remote proxy object-oriented interface
- provides optional user/password authentication and/or SSL encryption
- is extremely simple to use from client applications
- is connectionless, and assists transparent failover of communications
and services on a cluster of hosts
- has reasonable performance for a wide range of needs
- allows multiple language bindings
- for dynamic languages, requires no interface stub files
The "back end" (service side) of the OCS is nearing completion, and has
already been used successfully during two separate OCS engineering runs.
It is comprised of only a couple dozen processes, and provides automated
failover capabilities on a rack of commodity x86 Linux servers. We
provide an overview of the middleware design and its failover
capabilities. Some data on the performance of communications using the
middleware protocol is included.
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