Time domain science forms an increasing fraction of astronomical programs at many facilities. Synoptic and targeted observing modes of transient, varying, and moving sources rely on precise clocks to provide the underlying time tags. Often precision is mistaken for accuracy, or the precise time signals never reach the instrumentation in the first place. We will discuss issues of deploying a stable high-precision GNSS clock on a remote mountaintop, and of conveying the resulting time signals to a computer in a way that permits hardware timestamping of the camera shutter (or equivalent) rather than the arbitrary delays encountered with non-real-time data acquisition software. Strengths and limitations of the Network Time Protocol will be reviewed. Timekeeping infrastructure deployed for the Catalina Sky Survey will serve as an example.
A turnkey observatory with 6.5-m telescope has been developed for a broad range of science applications. The observatory includes the telescope, mount and enclosure, installed on site and ready for operation. The telescope’s primary mirror is an f/1.25 honeycomb sandwich of borosilicate glass, similar to that of the MMT and Magellan telescopes. The baseline optical design is for a Gregorian Nasmyth focus at f/11. A Gregorian adaptive optics secondary that provides a wide-field focus corrected for ground layer turbulence (0.25 arcsecond images over a 4 arcminute field) as well as a narrow-field diffraction-limited focus is optional. Another option is a corrected f/5 focus with a 1° field. The observatory, built by partners from academia and industry with extensive experience, can be delivered within five years at a fixed price.
The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is a joint effort of NOAO and the Department of Computer Science at the University of Arizona to build prototype software to process alerts from time-domain surveys, especially LSST, to identify those alerts that must be followed up immediately. Value is added by annotating incoming alerts with existing information from previous surveys and compilations across the electromagnetic spectrum and from the history of past alerts. Comparison against a knowledge repository of properties and features of known or predicted kinds of variable phenomena is used for categorization. The architecture and algorithms being employed are described.
The NOAO Data Lab will allow users to efficiently utilize catalogs of billions of objects, augment traditional telescope imaging and spectral data with external archive holdings, publish high level data products of their research, share custom results with collaborators and experiment with analysis toolkits. The goal of the Data Lab is to provide a common framework and workspace for science collaborations and individuals to use and disseminate data from large surveys.
In this paper we describe the motivations behind the NOAO Data Lab and present a conceptual overview of the activities we plan to support. Specific science cases will be used to develop a prototype framework and tools, allowing us to work directly with scientists from survey teams to ensure development will remain focused on scientifically productive tasks. This will additionally develop a pool of both scientific and technical experts who can provide ongoing advice and support for community users as the scope and capabilities of the Data Lab expand.
Proc. SPIE. 9149, Observatory Operations: Strategies, Processes, and Systems V
KEYWORDS: Observatories, Telescopes, Astronomy, Robotics, Control systems, Space telescopes, Astronomical telescopes, Space operations, Large Synoptic Survey Telescope, Atmospheric Cherenkov telescopes
Observatories are complex scientific and technical institutions serving diverse users and purposes. Their telescopes, instruments, software, and human resources engage in interwoven workflows over a broad range of timescales. These workflows have been tuned to be responsive to concepts of observatory operations that were applicable when various assets were commissioned, years or decades in the past. The astronomical community is entering an era of rapid change increasingly characterized by large time domain surveys, robotic telescopes and automated infrastructures, and – most significantly – of operating modes and scientific consortia that span our individual facilities, joining them into complex network entities. Observatories must adapt and numerous initiatives are in progress that focus on redesigning individual components out of the astronomical toolkit. New instrumentation is both more capable and more complex than ever, and even simple instruments may have powerful observation scripting capabilities. Remote and queue observing modes are now widespread. Data archives are becoming ubiquitous. Virtual observatory standards and protocols and astroinformatics data-mining techniques layered on these are areas of active development. Indeed, new large-aperture ground-based telescopes may be as expensive as space missions and have similarly formal project management processes and large data management requirements. This piecewise approach is not enough. Whatever challenges of funding or politics facing the national and international astronomical communities it will be more efficient – scientifically as well as in the usual figures of merit of cost, schedule, performance, and risks – to explicitly address the systems engineering of the astronomical community as a whole.
The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is a joint project of the National Optical Astronomy Observatory and the Department of Computer Science at the University of Arizona. The goal is to build the software infrastructure necessary to process and filter alerts produced by time-domain surveys, with the ultimate source of such alerts being the Large Synoptic Survey Telescope (LSST). The ANTARES broker will add value to alerts by annotating them with information from external sources such as previous surveys from across the electromagnetic spectrum. In addition, the temporal history of annotated alerts will provide further annotation for analysis. These alerts will go through a cascade of filters to select interesting candidates. For the prototype, ‘interesting’ is defined as the rarest or most unusual alert, but future systems will accommodate multiple filtering goals. The system is designed to be flexible, allowing users to access the stream at multiple points throughout the process, and to insert custom filters where necessary. We describe the basic architecture of ANTARES and the principles that will guide development and implementation.
We describe the design, construction and measured performance of the Kitt Peak Ohio State Multi-Object Spectrograph
(KOSMOS) for the 4-m Mayall telescope and the Cerro Tololo Ohio State Multi-Object Spectrograph (COSMOS) for
the 4-m Blanco telescope. These nearly identical imaging spectrographs are modified versions of the OSMOS
instrument; they provide a pair of new, high-efficiency instruments to the NOAO user community. KOSMOS and
COSMOS may be used for imaging, long-slit, and multi-slit spectroscopy over a 100 square arcminute field of view with
a pixel scale of 0.29 arcseconds. Each contains two VPH grisms that provide R~2500 with a one arcsecond slit and their
wavelengths of peak diffraction efficiency are approximately 510nm and 750nm. Both may also be used with either a
thin, blue-optimized CCD from e2v or a thick, fully depleted, red-optimized CCD from LBNL. These instruments were
developed in response to the ReSTAR process. KOSMOS was commissioned in 2013B and COSMOS was
commissioned in 2014A.
The astronomical time domain is entering an era of unprecedented growth. LSST will join current and future surveys at
diverse wavelengths in exploring variable and transient celestial phenomena characterizing astrophysical domains from
the solar system to the edge of the observable universe. Adding to the large but relatively well-defined load of a project
of the scale of the Large Synoptic Survey Telescope will be many challenging issues of handling the dynamic empirical
interplay between LSST and contingent follow-up facilities worldwide. We discuss concerns unique to this telescope,
while exploring consequences common to emerging observational time domain paradigms.
VOEvent is the emerging virtual observatory standard for representing and reporting celestial transient events. Detailed semantics and short latency are required to support immediate, often robotic, follow-up observations. A flexible schema supports a wide selection of instrumentation and observing scenarios. We discuss the use of VOEvent to motivate time domain astronomy in the NOAO Science Archive.
The NOAO Science Archive (NSA) is a step toward building a comprehensive scientific archive of the optical and infrared data holdings of the National Optical Astronomy Observatory. Earlier efforts included the NOAO Save the Bits archive (more properly a data store) with current raw data holdings from telescopes at both Kitt Peak National Observatory and Cerro Tololo Inter-American Observatory of more than 3 million images, totaling in excess of 20 terabytes. The NOAO Science Archive builds on the foundation provided by the NOAO Deep-Wide Field Survey (NDWFS) Archive that offers sophisticated analysis tools -- as well as the coherent and extensive NDWFS data set. NSA is an initiative of the NOAO Data Products Program aimed at identifying scientifically useful datasets from the large and growing NOAO holdings and making these data available to the astronomical community, while providing tools for data discovery, mining and exploration. The goals for the NSA are: to immediately create a scientifically useful archive of NOAO Survey data, to develop in-house expertise in the relevant technologies, to identify and document requirements for NOAO's future comprehensive archive by providing a design study, and to create a high level of visibility and utility for both the NOAO Archive and NOAO Surveys (for example, with web services available at http://archive.noao.edu). The archive and associated NOAO assets are expected to grow into a resource of the National Virtual Observatory.