The telescopes in Las Cumbres Observatory’s global network (LCO) operate robotically. The enclosures open and shut automatically, based on data provided by LCO’s own weather stations. In 2023, LCO began using images from all-sky cameras to estimate the sky transparency at its sites. For each image, the locations and opacities of clouds are revealed by comparing a smoothed visibility map (based on visible stars) with a catalog (i.e. unattenuated) visibility map. The cloud map is then multiplied by a weighting scheme that favors low airmasses to determine a single all-sky transparency. To calibrate the transparencies at which the enclosures should be opened or closed, LCO staff astronomers reviewed thousands of all-sky images acquired during partly cloudy nights. The reviews were performed independent of the transparency calculations, to avoid biasing the close/open decisions. Since deploying the all-sky transparency calculations to LCO’s sites, we have empirically determined that they provide a more accurate measure than IR cloud sensors of when sky conditions are appropriate for observing, and the time spent attempting to observe through clouds has been reduced.
Las Cumbres Observatory (LCOGT) operates a global network of robotic 0.4, 1.0, and 2.0-meter telescopes to facilitate scientific research and education in time-domain astronomy. LCOGT’s flagship educational program, Global Sky Partners (GSP), awards up to 1500 hours per year of telescope time to individuals and organizations that run their own, fully supported, educational programs. The GSP has a presence in 40 countries and 45% of the Partners target under-served, under-represented, and developing world audiences. The degradation and obsolescence of the original 0.4-meter telescope network prompted LCOGT to update the fleet of 10 telescopes to a new system consisting of predominantly off-the-shelf products. New PlaneWave DeltaRho 350 telescopes with Gemini Focuser/Rotators, LCOGT filter wheels, and QHY600 CMOS cameras, complement the original, custom-built mount. The deployment of all ten telescopes was completed in March 2024. We describe the design and performance of this new system and its components. We comment on modifications made to the QHY600 cameras, as well as on the treatment of random telegraph noise of its CMOS detectors within our data processing system BANZAI. The new telescope network supports the GSP program as well as multiple key science projects, including follow-up observations for the TESS satellite mission.
Las Cumbres Observatory global telescope (LCOGT) is a unique worldwide network of dynamically scheduled, fully robotic optical telescopes, purpose built for time domain astronomy. The LCOGT network enters its second decade of operations in 2024. A flood of transient alerts are expected from the Vera C. Rubin Legacy Survey of Space and Time (LSST) and multimessenger observatories. In 2023 LCOGT will complete the northern hemisphere 1-m telescope ring, currently four telescopes at McDonald and Teide Observatories, with the addition of two 1-m telescopes at Ali Observatory in Tibet. The southern ring is complete at the Siding Spring, Cerro Tololo and the South African Astronomical Observatories. LCOGT is an active partner in the Astrophysical Event Observatory Network (AEON) with NOIRLab facilities (Gemini Observatory, SOAR Observatory, and the Community Science and Data Center), to develop the infrastructure to efficiently carry out astronomical observations in the Vera C. Rubin Observatory LSST era. While the global pandemic has provided multiple operational challenges, hardware and software projects currently underway will make LCOGT an even more powerful transient follow-up facility in its second decade of operations.
Las Cumbres Observatory (LCOGT) operates a network of more than 25 telescopes that are globally distributed over seven sites. Despite the COVID-19 pandemic restricting travel to most of those sites since March 2020, LCOGT achieved several significant operational milestones: (i) We deployed a new multi-channel imager (MuSCAT3) at Haleakala Observatory. (ii) We installed two new 1-meter telescopes at Teide Observatory. (iii) We performed essential maintenance with local staff at the sites. The latter included opening two of the NRES spectrograph’s thermal and pressure enclosures - a task traditionally executed by trained LCOGT personnel only. We discuss the evolution of LCOGT’s paradigm for maintenance. Sustaining observatory operations increasingly relied on local observatory staff, of various skill levels and capabilities, to execute the highest priority work with remote support. We made this possible with extensive planning, being sensitive to local conditions, and bringing in expertise to support and guide in real-time via extended Zoom sessions.
Las Cumbres Observatory comprises 25 robotic telescopes hosting 6 instrument types at 7 sites. To manage the calibrations for such a large suite of instruments, LCO has developed a Target and Observation Manager (TOM) built on elements of the TOM Toolkit. In the Calibration-TOM, the fundamental assets to be managed are not astronomical targets (as with a TOM built for a science campaign) but the telescopes and instruments of the observatory. The Calibration-TOM is a web application that uses python code within a Django framework. Requests for recurring, nighttime calibrations are described by dynamic cadences, which are inserted into each instrument’s schedule with specified durations. In 2021, we began using the Calibration-TOM for observations of flux and RV standards for the NRES spectrographs, as well as for observations of photometric standards for all imagers. The Calibration-TOM makes the scheduling and outcomes of calibrations more transparent to operations personnel, expediting the identification of underperforming instruments. Other observatories supporting multiple instruments may benefit from creating similar TOM software.
The operation of robotic telescopes at remote locations without supervision by local staff is a specific challenge for Las Cumbres Observatory’s (LCOGT) global network, where more than 25 telescopes are operated at seven globally distributed sites. LCOGT personnel typically visits each site every 18 months for general maintenance and upgrade tasks, whereas minor failures are handled by local site support staff. LCOGT is making efforts to quantitatively inform decisions about scheduling preventative maintenance tasks and to provide tools to assist with failure diagnostic and response. For example, all night-time observations from all telescopes are analyzed to quantify the telescopes’ throughput; these data, updated daily and looking back more than four years, are used to inform the cadence of telescope mirror washing and recoating. Further examples of utilizing every day’s science data are presented, including monitoring the readnoise of more than 25 CCD cameras which has enabled the early detection of a failing CCD controller. Telemetry from all installations is collected in a no-SQL database (Opensearch) ∗ and presented to various stakeholders via the visualization tools Kibana and Grafana† . These utilities are used to diagnose problems in preprogrammed views, e.g., to detect acute issues or long-term degradation in the fleet of Cryotiger cooling systems. Telemetry data and performance metrics have always been collected at LCOGT. Making those data consistent, accessible, and easy to use for all stakeholders at LCOGT made the deluge of information usable in the daily observatory operation routine.
In Las Cumbres Observatory’s global network, the 1-meter telescopes are in greatest demand. Beginning in 2019, we undertook an investigation into the focus stability of these telescopes. We also refined the procedures for setting and maintaining optimal focus. The investigation showed the sensitivity of the telescopes’ optical components to temperature variations. The temperatures within the domes, as well as along the telescopes, are rarely stable for the first 80-120 minutes of science observations. A consequence is that start-of-night focus corrections must later be countered by additional corrections after thermalization. We report the various improvements to telescope focus that our investigation has spawned. The start-of-night focus corrections are now made immediately before science observations begin. Focus checks are now monitored during the night and trigger actionable alerts if they fail. Finally, we report on our effort to use the guide cameras as real-time focus sensors.
Las Cumbres Observatory is the only globally-distributed network of robotically-controlled telescopes. In 2018, we launched a program to overhaul the procedures by which network problems are detected, diagnosed and resolved. The program fostered numerous improvements, including new software tools to monitor active telescopes, documentation of recovery procedures, and daily reviews of operations problems. The benefit to users has been an increase in on-sky hours. We discuss the improvements we have made over the past two years. We emphasize the implementation of procedures ensuring problems are promptly addressed and completely resolved. We present our workflow as a model for how to manage a system of interconnected telescopes.
The Las Cumbres Observatory operates a fleet of robotically controlled telescopes currently two 2m, nine 1m, and ten 0.4m telescopes, distributed amongst six sites covering both hemispheres. Telescopes of an aperture class are equipped with an identical set of optical imagers, and those data are subsequently processed by a common pipeline (BANZAI). The telescopes operate without direct human supervision, and assessing the daily and long-term scientific productivity of the fleet of telescopes and instruments poses an operational challenge. One key operational metric of a telescope/instrument system is throughput. We present a method of long-term performance monitoring based on nightly science observations: For every image taken in matching filters and within the footprint of the PANSTARRS DR1 catalog we derive a photometric zeropoint, which is a good proxy for system throughput. This dataset of over 250000 data points enables us to answer questions about general throughput degradation trends, and how individual telescopes perform at the various sites. This particular metric is useful to plan the effort level for on-site support and to prioritize the cleaning and re-aluminizing schedule of telescope optics and mirrors respectively.
Work in time-domain astronomy necessitates robust, automated data processing pipelines that operate in real time. We present the BANZAI pipeline which processes the thousands of science images produced across the Las Cumbres Observatory Global Telescope (LCOGT) network of robotic telescopes each night. BANZAI is designed to perform near real-time preview and end-of-night final processing for four types of optical CCD imagers on the three LCOGT telescope classes. It performs instrumental signature removal (bad pixel masking, bias and dark removal, flat-field correction), astrometric fitting and source catalog extraction. We discuss the design considerations for BANZAI, including testing, performance, and extensibility. BANZAI is integrated into the observatory infrastructure and fulfills two critical functions: (1) real-time data processing that delivers data to users quickly and (2) derive metrics from those data products to monitor the health of the telescope network. In the era of time-domain astronomy, to get from these observations to scientific results, we must be able to automatically reduce data with minimal human interaction, but still have insight into the data stream for quality control.
With 18 telescopes distributed over 6 sites, and more telescopes being added in 2016, Las Cumbres Observatory Global Telescope Network is a unique resource for timedomain astronomy. The Network's continuous coverage of the night sky, and the optimization of the observing schedule over all sites simultaneously, have enabled LCOGTusers to produce significant science results. However, practical challenges to maximizing the Network's science output remain. The Network began providing observations for members of its Science Collaboration and other partners in May 2014. In the two years since then, LCOGT has made a number of improvements to increase the Network's science yield. We also now have two years' experience monitoring observatory performance; effective monitoring of an observatory that spans the globe is a complex enterprise. Here, we describe some of LCOGT's efforts to monitor the Network, assess the quality of science data, and improve communication with our users.
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