Astronomical Instruments Research Articles

How to Use the Italian Astronomical Heritage for the Dissemination of Scientific Knowledge in the Society

Astronomical Observatories are the most ancient scientific institutes in Italy. They preserve an incredible treasure made by rare books, astronomical sketches, documents and letters, and a noteworthy instrument collection used to realize discoveries and studies in the fields of classical astronomy and astrophysics. In the last few years the National Institute for Astrophysics has promoted a project to preserve, catalogue, and present a great part of the Italian astronomical heritage on the web with “Polvere di stelle”, the gate to arrive at the origin of modern astronomy in Italy. The studies made by some Italian researchers on the history of observatories, on the development of the astronomical instruments, on astronomers and their discoveries, activities, and scientific journeys, have revealed a complex pattern of relationships with other scientific and cultural communities, politicians and the society of their time. So you can study the foundation of Padua and Naples Observatories and you have to talk of Napoleon, Murat, and the Congress of Vienna. You can trace the birth of astrophysics and run into the events of the unification of Italy. Or you can be involved in the biographical study of Schiaparelli and you find yourself talking about archeology and fashion. And vice versa.To disseminate the scientific culture, and valorize the Italian astronomical heritage in a much wider context, we have realized exhibits, laboratories, and theatrical experiences to give life to cultural heritage. Through a powerful emotional involvement, these methods of non-formal communication of science establish a strong relationship between performers and spectators and give a more homogeneous view of the work of astronomers, and the cultural heritage they have left behind.This paper illustrates the projects we have created and the results obtained to transform the history of astronomy into the men’s stories.

Characterization of low light performance of a complementary metal-oxide semiconductor sensor for ultraviolet astronomical applications

Complementary metal-oxide semiconductor (CMOS) detectors offer many advantages over charge-coupled devices (CCDs) for optical and ultraviolet (UV) astronomical applications, especially in space where high radiation tolerance is required. However, astronomical instruments are most often designed for low light-level observations demanding low dark current and read noise, good linearity, and high dynamic range, characteristics that have not been widely demonstrated for CMOS imagers. We report the performance, over temperatures from 140 to 240 K, of a radiation hardened SRI 4k × 2k back-side illuminated CMOS image sensor with surface treatments that make it highly sensitive in blue and UV bands. After suppressing emission from glow sites resulting from defects in the engineering grade device examined, a 0.077 me − / s dark current floor is reached at 160 K, rising to 1 me − / s at 184 K, rivaling that of the best CCDs. We examine the trade-off between readout speed and read noise, finding that 1.43 e − median read noise is achieved using line-wise digital correlated double sampling at 700 kpix / s / ch corresponding to a 1.5 s readout time. The 15 ke − well capacity in high gain mode extends to 120 ke − in dual gain mode. Continued collection of photogenerated charge during readout enables a further dynamic range extension beyond 106 e − effective well capacity with only 1% loss of exposure efficiency by combining short and long exposures. A quadratic fit to correct for non-linearity reduces gain correction residuals from 1.5% to 0.2% in low gain mode and to 0.4% in high gain mode. Cross-talk to adjacent pixels is only 0.4% vertically, 0.6% horizontally, and 0.1% diagonally. These characteristics plus the relatively large (10 μm) pixel size, quasi 4-side buttability, electronic shutter, and sub-array readout make this sensor an excellent choice for wide field astronomical imaging in space, even at far-UV wavelengths where sky background is very low.

Structural, thermal, and optical performance analysis applied to subsystems of the European Extremely Large Telescope

Structural, thermal, and optical performance (STOP) analysis is gradually becoming a crucial tool in the development of optical systems in general and astronomical telescopes and instruments in particular. We describe the approach of the European Southern Observatory to STOP analysis at the examples of the phasing and diagnostic station and of the pre-focal station of the European Extremely Large Telescope under construction. Further, we discuss the fundamentals of the estimation of thermal effects on optical performance and how to carry it out with the in-house developed software tool Sensitizer.

Special Section Guest Editorial: The SKA Observatory

The <i>Journal of Astronomical Telescopes, Instruments, and Systems</i> (JATIS) publishes peer-reviewed papers reporting on original research in the development, testing, and application of telescopes, instrumentation, techniques, and systems for ground- and space-based astronomy.

TIFR treasures for astronomy from ground to space

The infrared astronomy group of Department of Astronomy and Astrophysics at Tata Institute of Fundamental Research has been pursuing astronomical instrumentation activities since its inception. The group has been routinely involved in balloon-borne astronomy programs from the field station at Hyderabad with indigenously developed payloads. Ground-based astronomical activities began with a single element infrared detector. Later, over time, larger format array detectors are being used in the cameras. These astronomy cameras have been routinely used at observatories across India. Recently, the group has also developed a laboratory model of the Infrared Spectroscopic Imaging Survey payload, targeted for the small satellite mission of the Indian Space Research Organisation, which will carry out spectroscopic measurements in the wavelength range 1.7 to 6.4 $\mu$m seamlessly

Astronomy in Kazan in the 19th centurу

The article reveals brief history of the origin of Kazan astronomy and its development in the 19th century. Special attention is paid to the construction of the Observatory building and equipping it with astronomical instruments. Examples of scientific achievements are given. The scientific work of M.A. Kowalski is described in more detail.

Trieste CALLISTO station setup and observations of solar radio bursts

The Trieste CALLISTO station ( http://radiosun.oats.inaf.it ) was established in 2012 at the Basovizza Observing Station (45°38′37′' N, 13°52′34 E'', 398 m above MSL) operated by the Italian National Institute for Astrophysics (INAF) - Astronomical Observatory of Trieste (Italy) to study solar radio bursts and the response of the Earth’s ionosphere and geomagnetic field. To date, three ‘Compound Astronomical Low-cost Low frequency Instrument for Spectroscopy and Transportable Observatory’ (CALLISTO) spectrometers have been installed, with the capability of observing in the frequency ranges 45–80 MHz (from 30 December 2014), 220–420 MHz (from 1 June 2012 to 23 October 2012 and from 5 October 2013), 905–1730 MHz (from 30 December 2019). The three receivers are fed respectively by a dipole, log-periodic and cross-dipole antenna. Nominally, frequency spectra are obtained with 4 sweeps per second over in total 600 channels. Here, we describe the Trieste CALLISTO station setup, the local e-Callisto network digital archive, Trieste CALLISTO Radio Bursts Detection and Visualization System available via web and present dynamic spectra of a sample of Type I, II, III, IV and V radio bursts. As an additional feature, we show also its capability to record lightning strikes.

Low-cost Access to the Deep, High-cadence Sky: the Argus Optical Array

New mass-produced, wide-field, small-aperture telescopes have the potential to revolutionize ground-based astronomy by greatly reducing the cost of collecting area. In this paper, we introduce a new class of large telescope based on these advances: an all-sky, arcsecond-resolution, 1000 telescope array which builds a simultaneously high-cadence and deep survey by observing the entire sky all night. As a concrete example, we describe the Argus Array, a 5 m-class telescope with an all-sky field of view and the ability to reach extremely high cadences using low-noise CMOS detectors. Each 55 GPix Argus exposure covers 20% of the entire sky to m g = 19.6 each minute and m g = 21.9 each hour; a high-speed mode will allow sub-second survey cadences for short times. Deep coadds will reach m g = 23.6 every five nights over 47% of the sky; a larger-aperture array telescope, with an étendue close to the Rubin Observatory, could reach m g = 24.3 in five nights. These arrays can build two-color, million-epoch movies of the sky, enabling sensitive and rapid searches for high-speed transients, fast-radio-burst counterparts, gravitational-wave counterparts, exoplanet microlensing events, occultations by distant solar system bodies, and myriad other phenomena. An array of O(1000) telescopes, however, would be one of the most complex astronomical instruments yet built. Standard arrays with hundreds of tracking mounts entail thousands of moving parts and exposed optics, and maintenance costs would rapidly outpace the mass-produced-hardware cost savings compared to a monolithic large telescope. We discuss how to greatly reduce operations costs by placing all optics in thermally controlled, sealed domes with only a few moving parts. Coupled with careful software scope control and use of existing pipelines, we show that the Argus Array could become the deepest and fastest Northern sky survey, with total costs in the $20M range.

James Walter (Jim) Warwick (1924–2013)

Warwick helped establish the field of low frequency radio astronomy. He was principal investigator for NASA’s Voyager I and II Planetary Radio Astronomy instruments, that measured the radio emission from Jupiter, Saturn, Uranus and Neptune.

Development and validation of an astronomy self-efficacy instrument for understanding and doing

This paper presents a new astronomy self efficacy instrument, composed of two factors, one relating to learning astronomy content, which we call astronomy personal self efficacy, and the other relating to the use of astronomical instrumentation, specifically the use of remote robotic telescopes for data collection. The latter is referred to as the astronomy instrumental self efficacy factor. The instrument has been tested for reliability and construct validity. Reliability testing showed that factor 1 had a Cronbachs alpha of 0.901 and factor 2 had a Cronbachs alpha of 0.937. Construct validity was established by computing one way analyses of variances, with the p value suitably protected, using independent variables peripherally related to the constructs. These analyses demonstrate that both scales possess high construct validity. The development of this astronomy specific instrument is an important step in evaluating self efficacy as a precursor to investigating the construct of science identity in the field of astronomy.

Design, implementation, and qualification of high-performance time and frequency reference for the MeerKAT telescope (Erratum)

The <i>Journal of Astronomical Telescopes, Instruments, and Systems</i> (JATIS) publishes peer-reviewed papers reporting on original research in the development, testing, and application of telescopes, instrumentation, techniques, and systems for ground- and space-based astronomy.

TeV Instrumentation: Current and Future

During the last 20 years, TeV astronomy has turned from a fledgling field, with only a handful of sources, into a fully-developed astronomy discipline, broadening our knowledge on a variety of types of TeV gamma-ray sources. This progress has been mainly achieved due to the currently operating instruments: imaging atmospheric Cherenkov telescopes, surface arrays and water Cherenkov detectors. Moreover, we are at the brink of a next generation of instruments, with a considerable leap in performance parameters. This review summarizes the current status of the TeV astronomy instrumentation, mainly focusing on the comparison of the different types of instruments and analysis challenges, as well as providing an outlook into the future installations. The capabilities and limitations of different techniques of observations of TeV gamma rays are discussed, as well as synergies to other bands and messengers.

First Solar Radio Burst Observations by the Mexican Array Radio Telescope (MEXART) at 140 MHz

The National Laboratory of Space Weather in Mexico (Laboratorio Nacional de ClimaEspacial: LANCE) coordinates instrumentation for monitoring the space-weatherimpact over Mexico. Two of these instruments are the Mexican Array Radio Telescope(MEXART) and Compound Astronomical Low frequency Low cost Instrument for Spectroscopy and Transportable Observatory(CALLISTO) station from the e-CALLISTO network (CALLMEX). Both instruments are located at the same facility(Coeneo Michoacan, Mexico) and share a spectral band centered at 140 MHz. In this work we show the capabilities of the e-CALLISTO network as support to identify a solar radio burst in the signal of the MEXART radiotelescope. We identify 75 solarradio bursts in the MEXART signal: five events of Type II and 70 of Type III between September 2015 and May 2019. The analysis of solar radio bursts in the MEXART signal provide us valuable information about the development of the radio event due their high sensitivity, time resolution, and isotropic response. For the case of Type III solar radio events, we identify three characteristic phases in the dynamical evolution ofthe signal at 140 MHz: a pre-phase, a main peak, a decay phase, and a post-event phase.A Morlet wave transform was done of MEXART signals in the Type III solar radiobusts; in their spectra it was identified a pine tree structure preceding the main event in the time series. These characteristics are not observable in the data from the e-Callistonetwork.

Multi-line Observations, Models, and Data Needed to Understand the Nature of UV-irradiated Interstellar Matter

Far-ultraviolet photons from OB-type massive stars regulate the heating, ionization, and chemistry of much of the neutral interstellar gas in star-forming galaxies. The interaction of FUV radiation and interstellar matter takes place in environments broadly known as photodissociation regions (PDRs). PDR line diagnostics are the smoking gun of the radiative feedback from massive stars. Improving our understanding of stellar feedback in the ISM requires quantifying the energy budget, gas dynamics, and chemical composition of PDR environments. This goal demands astronomical instrumentation able to deliver multi-line spectroscopic images of the ISM (of the Milky Way and nearby galaxies). It also requires interdisciplinary collaborations to obtain the rate coefficients and cross sections of the many microphysical processes that occur in the ISM and that are included in models such as the Meudon PDR code.

Objects in Frames: Displaying Foreign Collectibles in Early Modern China and Europe by Anna Grasskamp

Reviewed by: Objects in Frames: Displaying Foreign Collectibles in Early Modern China and Europe by Anna Grasskamp Andrea Bubenik Grasskamp, Anna, Objects in Frames: Displaying Foreign Collectibles in Early Modern China and Europe, Berlin, Dietrich Reimer, 2019; hardback; pp. 246; 81 colour, 12 b/w illustrations; R.R.P. €39.00; ISBN 9783496016243. What does it mean to frame collectible objects, as opposed to paintings, or works on paper? How is the framing of objects culturally determined? Does framing always render context irrelevant? This ambitious book proposes a transcultural approach to these questions and focuses on a variety of compelling case studies from China and Europe. Rather than offer a solely empirical or comparative approach, the philosophical and sociological dimensions of framing are also probed, with the author also showing a keen eye for the nuances of cultural difference. The concept of a frame has been much discussed regarding the two dimensional, but less attention has been paid to how three-dimensional objects have historically been framed and displayed. A great strength here is the focus on porcelain and coral fragments which were highly valued in the burgeoning court collections of the period. While the Kunstkammern and curiosity cabinets of Europe are well-known, less attention has been given to correspondent Chinese systems of display. Indeed, Anna Grasskamp’s book challenges the binary divisions of ‘Europe’ and ‘Asia’, ‘Netherlandish’, or ‘Chinese’, and instead allows for a more fluid and comparative approach to probe culturally defined systems of collecting and display. Chapter 1 focuses on how ‘foreign’ goods, including Chinese porcelain, were framed and mounted in sixteenth- and seventeenth-century Kunstkammern. Chapter 2 takes the same approach but in the Chinese context, considering how European astronomical instruments were reframed at Chinese courts. Chapters 3 and 4 focus on the framing of foreign and natural objects in European Renaissance and Chinese Ming Dynasty collections. These chapters, with their focus on refashioned coral, are especially strong, probing how coral was perceived in both cultures as transformative ‘matter’ and related to resurrections and metamorphoses with Christ and Ovid on the one hand, and Buddhist worship on the other. Grasskamp rightfully points to the landmark publication of Exhibiting Cultures (Smithsonian Institute, 1991), and it is in this lineage that her book should be considered. The recent Getty publication of Samuel Quiccheberg’s Inscriptiones of 1565 (Getty Publications, 2013), one of the first museological texts, will also heighten interest in the themes and issues raised here. Overall, there is a sense that it is important to tend to the lives of objects, especially in the early modern period, an era that is increasingly recognized as global not only for its trade routes but also the circulation of objects and related ideas. [End Page 281] Andrea Bubenik The University of Queensland Copyright © 2022 Andrea Bubenik

HILIGT, Upper Limit Servers II — Implementing the data servers

The High-Energy Lightcurve Generator (HILIGT) is a new web-based1 tool which allows the user to generate long-term lightcurves of X-ray sources. It provides historical data and calculates upper limits from image data in real-time. HILIGT utilizes data from twelve satellites, both modern missions such as XMM-Newton and Swift, and earlier facilities such as ROSAT, EXOSAT, Einstein or Ariel V. Together, this enables the user to query 50 years of X-ray data and, for instance, study outburst behavior of transient sources. In this paper we focus on the individual back-end servers for each satellite, detailing the software layout, database design, catalog calls, and image footprints. We compile all relevant calibration information of these missions and provide an in-depth summary of the details of X-ray astronomical instrumentation and data.

High Accuracy Pointing for Quasi-Optical THz Mixer Arrays

We report a high accuracy pointing technique for quasi-optical hot electron bolometer (HEB) mixers in focal-plane arrays designed to operate at 1.4, 1.9, and 4.7 THz. The high accuracy pointing is achieved by prealignment of a HEB chip to a lens, measuring the angular error of each mixer in an array assembly, and then realignment of the chip to the same lens to correct the error. The realigned mixers, using 5 mm diameter Si elliptical lenses designed for operation at 4.7 THz, show a final pointing error distribution with an average (μ) = 0.13° and standard deviation ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">σ</i> ) = 0.06°, with respect to the normal direction of the respective array plane. Those using 10 mm diameter lenses designed for operation either at 1.4 or 1.9 THz, show μ = 0.08° and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">σ</i> = 0.03°. We demonstrated our pointing technique in five 4×2 HEB focal plane arrays developed for NASA's balloon borne GUSTO THz observatory. Our results corroborate the simulated beam steering factors used to calculate the realignment corrections. With the unprecedented pointing accuracy at the high frequencies, our technique can significantly facilitate the use of lens-antenna, quasi-optical mixers for future focal-plane arrays, which is able to compete with traditional feedhorn-waveguide mixer arrays, operated typically below 1 THz, for astronomical instrumentation.

A Prototype of a Large Tunable Fabry–Pérot Interferometer for Solar Spectroscopy

Large Fabry–Pérot Interferometers (FPIs) are used in a variety of astronomical instrumentation, including spectro-polarimeters for 4 m class solar telescopes. In this work we comprehensively characterize the cavity of a prototype 150 mm FPI, sporting a novel, fully symmetric design. Of particular interest, we define a new method to properly assess the gravity effects on the interferometer’s cavity when the system is used in either the vertical or horizontal configuration, both typical of solar observations. We show that the symmetric design very effectively limits the combined effects of pre-load and gravity forces to only a few nm over a 120 mm diameter illuminated surface, with gravity contributing ∼2 nm peak-to-valley (∼0.3 nm rms) in either configuration. We confirm a variation of the tilt between the plates of the interferometer during the spectral scan, which can be mitigated with appropriate corrections to the spacing commands. Finally, we show that the dynamical response of the new system fully satisfies typical operational scenarios. We conclude that large, fully symmetric FPIs can be safely used within solar instrumentation in both, horizontal and vertical position, with the latter better suited to limiting the overall volume occupied by such an instrument.

Polarization modeling and predictions for DKIST, part 9: flux distribution with FIDO

Astronomical instruments greatly improve wavelength multiplexing capabilities by using beam splitters. In the case of the 4-m National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST) solar telescope, over 70 W of optical power is distributed simultaneously to four instruments, each with multiple cameras. Many DKIST observing cases require simultaneous observations of many narrow bandpasses combined with an adaptive optics system. The facility uses five dichroic optical stations to allow at least 11 cameras and two wavefront sensors to simultaneously observe ultraviolet to infrared wavelengths with flexible reconfiguration. The DKIST dichroics required substantial development to achieve very tight specifications over very large apertures of 290 mm diameter. Coating spectral variation occurs over <1 nm wavelength, comparable with instrument bandpasses. We measure retardance spectral variation of up to a full wave and diattenuation varying over ±10 % per nm. Spatial variation of Mueller matrix elements for coatings in both transmission and reflection requires careful metrology. We demonstrate coatings from multiple vendors exhibit this behavior. We show achievement of 5-nm root mean square (RMS) reflected wavefront and 24-nm RMS power with coatings over 8 μm thick. We show mild impacts of depolarization and spectral variation of polarization on modulation efficiency caused by the dichroic coatings. We show an end-to-end system polarization model for the visible spectropolarimeter instrument, including the dichroics, grating, analyzer, and all coated optics. We show detailed performance for all DKIST dichroics for community use in planning future observations.

Smart Readout of Nondestructive Image Sensors with Single Photon-Electron Sensitivity.

Image sensors with nondestructive charge readout provide single-photon or single-electron sensitivity, but at the cost of long readout times. We present a smart readout technique to allow the use of these sensors in visible light and other applications that require faster readout times. The method optimizes the readout noise and time by changing the number of times pixels are read out either statically, by defining an arbitrary number of regions of interest in the array, or dynamically, depending on the charge or energy of interest in the pixel. This technique is tested in a Skipper CCD showing that it is possible to obtain deep subelectron noise, and therefore, high resolution of quantized charge, while dynamically changing the readout noise of the sensor. These faster, low noise readout techniques show that the skipper CCD is a competitive technology even where other technologies such as electron multiplier charge coupled devices, silicon photo multipliers, etc. are currently used. This technique could allow skipper CCDs to benefit new astronomical instruments, quantum imaging, exoplanet search and study, and quantum metrology.