Our current understanding of cosmology is largely shaped by Type Ia supernovae (SNe Ia), the detonations of carbon-oxygen white dwarves (WDs). SNe Ia are powerful standard candles due to their uniform peak luminosities which decay predictably. SNe Ia progenitor system architecture is highly debated, as none have been observed pre- and post-detonation. Within the first few days after detonation, critical progenitor signatures are preserved in the ultraviolet (UV) bandpass. We present the optical design of UVIa, a proposed 12U CubeSat capable of simultaneous measurements in the far-UV, near-UV, and u-band. Double-offset Cassegrain telescopes were designed to image onto CMOS detectors. We discuss the benefits and challenges associated with double-offset telescopes. UVIa additionally serves as a technology demonstration platform for several cutting-edge UV technologies. The optical design of UVIa enables early-time observations of SNe Ia and serves as a pathfinder for future UV transient telescopes.
Type Ia supernovae (SNe Ia) are a cornerstone of modern cosmology. Upcoming missions like the Nancy Grace Roman Telescope are pushing to high redshifts to measure cosmological parameters like the dark energy equation of state. Despite the impressive success of empirically standardizing their luminosities, the explosion mechanism of SNe Ia remains hotly debated; e.g., the mass of the white dwarf (WD) when it explodes and the state of the companion star (degenerate or non-degenerate) are all currently in question.
Early-time UV observations are sensitive to the outermost layers of the ejecta (and least affected by the explosion itself) and show the most diversity for SNe Ia. This makes the UV bandpass an excellent probe to solve these open questions about the nature of these cosmological distance indicators. To achieve this science, we present UVIa, a CubeSat that will be reactive and have simultaneous optical, Near-UV (NUV), and Far-UV (FUV) coverage, takes advantage of state-of-the-art UV coatings, UV-enhanced silicon detectors with whitelight rejection filter, and autonomous observing scheduling, updated regularly based on newly discovered SNe Ia from modern transient surveys.
Moving into the age of Time Domain Astronomy, robust, automated data reductions systems become essential. Here we present BANZAI-FLOYDS, a fully automated long-slit data reduction pipeline for the FLOYDS spectrograph at Las Cumbres Observatory. BANZAI-FLOYDS is fully written in Python, implementing wavelength calibration, fringe correction, object detection and tracing, telluric correction and flux calibration. The pipeline builds on the BANZAI library which handles the data flow and engineering allowing BANZAI-FLOYDS to only focus on spectroscopic processing. This design enables modularity of the processing stages allowing rapid development and encourages reuse for other spectrographs.
KEYWORDS: Astronomy, Photometry, Spectroscopy, Databases, Astrophysics, Data archive systems, Astrometry, Astronomical software, Open source software, Data transmission, Data storage
Introducing HERMES (HOP Enabled Rapid Message Exchange Service), an application which supports sharing and querying structured data containing targets, photometry, spectroscopy, astrometry, and more. Many branches of astronomy, particularly time-domain and multimessenger astrophysics, are driven by time-critical alerts. Coordinating the community-wide response to provide characterization observations of the alerts is critical to realizing many of the science goals in these fields. As part of the SCIMMA (Scalable CyberInfrastructure to support multimessenger astrophysics) project, HERMES provides a platform for users to share messages and data in a structured format that can be sent over the SCIMMA Kafka streams, while also delivering a queryable database of those messages. The goal of HERMES is to encourage more astronomers to share data in a common, machine-readable format. While the platform is robust and general enough to handle many kinds of astrophysical data, HERMES is especially useful for non-localized event follow-up such as gravitational wave or neutrino events and maintains relationships between non-localized events and related messages and targets of interest. We discuss the Domain-Specific Language (DSL) designed for sharing structured astronomical data through HERMES, which also supports formatting and submitting data to external services such as NASA’s GCN (General Coordinates Network) circulars or the TNS (Transient Name Server). Finally, we present the integration between HERMES and TOM (Target and Observation Management) Toolkit based systems, allowing TOM users to share or ingest data through HERMES.
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.
Time domain astronomy has both increased the data volume and the urgency of data reduction in recent years. Spectra provide key insights into astrophysical phenomena but require complex reductions. Las Cumbres Observatory has six spectrographs - two low-dispersion FLOYDS instruments and four NRES high-resolution echelle spectrographs. We present an extension of the data reduction framework, BANZAI, to process spectra automatically, with no human interaction. We also present interactive tools we have developed for human vetting and improvement of the spectroscopic reduction. Tools like those presented here are essential to maximize the scientific yield from current and future time domain astronomy.
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.
We report the development of MuSCAT3, a four channel simultaneous imager installed on the 2m Faulkes Telescope North at Haleakala Observatory on Maui, Hawai’i. MuSCAT3 has a capability of 4-color simultaneous imaging in g (400–550 nm), r (550–700 nm), i (700–820 nm), and zs (820–920 nm) bands with four independent 2048×2048 pixel CCDs, each having a field of view of 9.1×9.1 arcmin2 with a pixel scale of 0.27 arcsec per pixel. The development of MuSCAT3 started from September 2019, and MuSCAT3 achieved its first light on September 28th, 2020. The Las Cumbres Observatory started science operations of MuSCAT3 since November 4th, 2020, although a part of its capabilities are still limited.
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.
Las Cumbres Observatory Global Telescope Network (LCOGT) has built the Network of Robotic Echelle Spectrographs (NRES), consisting of four identical, high-resolution optical spectrographs, each fiber-fed simultaneously by up to two 1-meter telescopes and a calibration source. Two units have been installed and are currently executing scientific observations. A third unit has been installed and is presently in commissioning. A fourth unit has been shipped to site and will be installed in mid 2018. Operating on four separate continents in both the Northern and Southern hemispheres, these instruments comprise a globally-distributed, autonomous spectrograph facility for stellar classification and high-precision radial velocity of bright stars. Simulations suggest we will achieve long-term radial velocity precision of 3 m/s in less than an hour for stars with V < 12. Radial velocity precision of 75 m/s has already been demonstrated with our automatic data-processing pipeline across multiple sites. Work is ongoing to improve several NRES system components including telescope control (robotic source acquisition in particular) and the data-processing pipeline. In this document we briefly overview the NRES design, its purpose and goals, results achieved to date in the field, and the ongoing development effort to improve instrument performance.
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