Astronomical Instruments Research Articles

Sistem Kontrol Teleskop Ioptron AZ Mount Pro Berbasis Android

The development of astronomical observation instrument technology makes astronomical observations easier and simpler. One of them is a telescope equipped with a computerized motor. Control of the telescope can now be done wirelessly through an android application on a smartphone, one of which is the Sky Safari Plus 6 application. By using the Ioptron AZ Mount Pro telescope, the telescope can be controlled using the Sky Safari Plus 6 application wirelessly via a smartphone without using a computer and additional driver.

EXPLANATION: Exoplanet and Transient Event Investigation Project—Optical Facilities and Solutions

Over the past decades, the achievements in astronomical instrumentation have given rise to a number of novel advanced studies related to the analysis of large arrays of observational data. One of the most famous of these studies is a study of transient events in the near and far space and a search for exoplanets. The main requirements for such kinds of projects are a simultaneous coverage of the largest possible field of view with the highest possible detection limits and temporal resolution. In this study, we present a similar project aimed at creating an extensive, continuously updated survey of transient events and exoplanets. To date, the core of the project incorporates several 0.07–2.5 m optical telescopes and the 6-m BTA telescope of the Special Astrophysical Observatory of RAS (Russia), a number of other Russian observatories and the Bonhyunsan observatory of the Korea Astronomy and Space Science Institute (South Korea). Our attention is mainly focused on the description of two groups of small, wide-angle optical telescopes for primary detection. All the telescopes are originally designed for the goals of the project and may be of interest to the scientific community. A description is also given for a new, high-precision optical spectrograph for the Doppler studies of transient and exoplanet events detected within the project. We present here the philosophy, expectations and first results obtained during the first year of running the project.

CHOKAN VALIKHANOV’S ROLE IN THE DEVELOPMENT OF ORIENTAL SCIENCE

The article focuses on the research of Ch.Valikhanov of the closed cities of Kashgar. In addition, it is interesting for scientists to study the geography of the Tien Shan, with accurate drawing of objects on maps, ethnographic research, which made it possible to learn a lot about the life and culture of the peoples of Central Asia. It is noted that one of the significant contributions of the scientist to world science is the fragment of the epic “Manas” recorded and translated by him, which is still recognized as the best translation. His report “On the state of Altyshar ...” was published in an abridged version and was soon translated into English, German and French. The full text was published only in 1904. The publication of this book made Chocan one of the most famous oriental scholars of his time. The scientist’s research on the spiritual and material culture of the Kazakh people is a valuable source on the history of Kazakhstan. It should also be noted that Ch. Ch. Valikhanov, during his trips, mainly relied on eye-measuring surveys. And when traveling to Kashgaria, it was not possible to use geodetic or astronomical instruments at all. It was under such circumstances that Chokan discovered a masterful skill in describing and characterizing the areas he saw and mapping them. Key words: Ch. Valikhanov, Kashgar, Kazakhstan, Central Asia, orientalist, maps

Exascale integrated modeling of low-order wavefront sensing and control for the Roman Coronagraph instrument.

Astronomical instruments to detect exoplanets require extreme wavefront stability. For these missions to succeed, comprehensive and precise modeling is required to design and analyze suitable coronagraphs and their wavefront control systems. In this paper, we describe techniques for integrated modeling at scale that is, to the best of our knowledge, 1000 times faster than previously published works. We show how this capability has been used to validate performance and perform uncertainty quantification for the Roman Coronagraph instrument. Finally, we show how this modeling capacity may be necessary to design and build the next generation of space-based coronagraph instruments.

Performance of Sequential Phase Diversity with Dynamical Solar Scenes

Phase diversity techniques are usually based on the comparison of synchronously acquired pairs of focused–defocused images. This way, differences between both images are avoided except from random pixel variations due to noise on the detector and the phase diversity itself. In some astronomical instruments, though, the two images are not taken simultaneously. This work studies the impact of carrying out phase diversity with pairs of asynchronously acquired images while observing an evolving solar scene. We evaluate the performance of this technique as a function of the time gap between the images through the use of a magnetohydrodynamical simulation of the solar scene as observed by an instrument. We describe the incident wave front with two numbers of Zernike polynomials (20 or 32) to explore their effect on the wave front sensing accuracy and we employ two levels of noise to study their impact in the object restoration. We find that a time gap among our simulation images smaller than ∼10 s has a negligible impact on the performance of the method. The rms error of the Zernike coefficients fitting worsens exponentially from there on, but the evolution is similar no matter the number of polynomials used in the fitting. Meanwhile, the quality of the object restoration benefits from lower noise levels, but it decreases linearly with the time gap independently of the amount of noise.

Super-resolution wavefront reconstruction

Context.Cutting-edge, ground-based astronomical instruments are fed by adaptive optics (AO) systems that are aimed at providing high performance down to the visible wavelength domain on 10 m class telescopes and in the near infrared for the first generation instruments of Extremely Large Telescopes (ELTs). Both applications lead to a large ratio between the telescope diameter,D, and the coherence length or Fried parameter,r0, that isD/r0. As the parameter that defines the required number of degrees of freedom of the AO system,D/r0drives the requirement to reconstruct the incoming wavefront with ever-higher spatial resolution. In this context, super-resolution (SR) appears as a potential game changer. Indeed, SR promises to dramatically expand the range of spatial frequencies that can be reconstructed from a set of lower resolution measurements of the wavefront.Aims.As a technique that seeks to upscale the resolution of a set of measured signals, SR retrieves higher-frequency signal content by combining multiple lower resolution sampled data sets. It is well known both in the temporal and spatial domains and widely used in imaging to reduce aliasing and enhance the resolution of coarsely sampled images. This study applies the SR technique to the bidimensional wavefront reconstruction. In particular, we show how SR is intrinsically suited for tomographic multi-wavefront sensor (WFS) AO systems, revealing many of its advantages with minimal design effort.Methods.We provide a direct space and Fourier optics description of the wavefront sensing operation and we demonstrate how SR can be exploited through signal reconstruction, especially within the framework of periodic non-uniform sampling. We investigate both meta-uniform and non-uniform sampling schemes and we show that under some conditions, both sampling schemes enable a perfect reconstruction of band-limited signals. We also provide a SR bi-dimensional model for a Shack-Hartmann (SH) WFS, along with an analysis of the characteristics of the sensitivity function. We validated the SR concept with numerical simulations of representative multi-WFS SH AO systems. Finally, we explored the extension of the method to pyramid WFSs.Results.Our results show that combining several WFS samples in a SR framework grants access to a greater number of modes than the native one offered by a single WFS (despite the fixed sub-aperture size across samples). We show that the wavefront reconstruction achieved with four WFSs can be equivalent to a single WFS providing a sampling resolution that is twice greater (linear across the telescope aperture). We also show that the associated noise propagation is not degraded under SR. Finally, we show that the concept can be extended to the signal produced by single pyramid WFS, with its four re-imaged pupils serving as multiple non-redundant samples.Conclusions.We find that SR applied to wavefront sensing and reconstruction (WFR) offers a new parameter space to explore, as it decouples the size of the sub-aperture from the desired wavefront sampling resolution. By shifting away from outdated assumptions, new and more flexible, better-performing AO designs have now become possible.

Echelle Grating Spectroscopic Technology for High-Resolution and Broadband Spectral Measurement

Echelle grating provides high spectral resolving power and diffraction efficiency in a broadband wavelength range by the Littrow mode. The spectrometer with the cross-dispersed echelle scheme has seen remarkable growth in recent decades. Rather than the conventional approach with common blazed grating, the cross-dispersed echelle scheme achieves the two-dimensional spatial distribution of the spectrum by one exposure without scanning in the broadband spectral range. It is the fastest and most sensitive spectroscopic technology as of now, and it has been extensively applied in commercial and astronomical spectrometers. In this review, we first highlight the characteristics of the echelle and then present the optical layout, detection approach, and method of calibration. Finally, we discuss the state-of-the-art implementations and applications of commercial and astronomical instruments.

Importance of laboratory experimental studies of silicate grains for exoplanet atmosphere characterization

The study of exoplanetary atmospheres extends the frontiers of astronomy, astrophysics, and astrochemistry. Moreover, studies of exoplanets as being linked to the search for extraterrestrial life and other habitable planets are of interest not only for scientists, but for a much wider public audience. There is much evidence that clouds exist and are common in the exoplanetary atmospheres at high temperatures. Their origin can be gas-phase condensation of silicate materials and other refractory materials. Clouds have a major impact on the planets’ observable properties. Models describing atmospheres of exoplanets and brown dwarfs point to the necessity of including nanometer-to micrometer-sized grains of silicates. Observational mid-IR spectra have also provided tentative evidence of silicate grain absorption. Thus, silicates seem to be the first target for future astronomical observations of cloudy atmospheres and for laboratory studies supporting these observations. However, high-temperature laboratory studies of optical and structural properties of refractory materials, including silicates, and of gas-grain and grain surface chemistry needed for the decoding of astronomical spectra and for the development of reliable atmospheric models present practically uncharted territory. The aim of our paper is to review previous studies of optical and chemical properties of silicate materials and to emphasize the importance and perspective of high-temperature measurements of laboratory analogues of atmospheric silicate grains for exoplanet atmosphere characterization. This is particularly important in the light of new advanced astronomical instruments, which, as we expect, will bring comprehensive information on exoplanetary atmospheres.

The Stability of Fiber Spectrographs in the Faint-source Regime

The use of optical fibers in astronomical instrumentation offers high-multiplex and light-gathering flexibility. However, with most previous fiber spectrographs optimized for large fields of view on modest-aperture telescopes, the performance of fibers in the context of faint targets on large telescopes remains largely untested. In this paper, we evaluate aspects of fiber stability, especially as they apply in the context of precision sky subtraction of faint sources at modest spectral resolution (R ∼ 3000). After introducing a framework for describing potential systematic errors, we use publicly available data from existing instruments, including instrumentation used by the fourth-generation Sloan Digital Sky Survey’s MaNGA project (MaNGA: Mapping Nearby Galaxies at Apache Point Observatory) and the Very Large Telescope’s FLAMES: Fiber Large Array Multi Element Spectrograph. We isolate sources of fiber systematics and estimate the observed amplitude of persistent residuals as well as stochastic noise contributions resulting from changing fiber stresses. Comparing these levels against their impact on various sky subtraction schemes demonstrates that 0.1% precision sky subtraction with fiber instruments is possible. As a demonstration, we show that the MaNGA instrument can deliver 0.2% residuals on bright near-IR sky lines with nonlocal sky subtraction, if pseudo-slit limitations are addressed by allocating 50% of its fibers to sky. We further highlight recently published deep exposures that achieved a 1σ background level of 27.6 AB per square arc second, equivalent to a precision of 0.2% of the sky background continuum.

The torquetum (or turketum): Was it an observing instrument?

The torquetum was a complex astronomical instrument whose construction is known thanks to certain descriptions, iconography and few extant artefacts. It was used in pre-telescopic astronomy from at least the 13th century. However, the usefulness of the torquetum as an observing instrument remains unknown. It is my intention to introduce a preliminary analysis of the merits and limitations of the torquetum in determining the coordinates of celestial bodies. For this purpose I shall refer to (1) written sources that contain descriptions of the construction of the instrument and its use; (2) the results of an examination of the torquetum constructed by Hans Dorn of Vienna (c.1487) and conserved in the Jagiellonian University Museum in Cracow; (3) elements of a theory of the instrument, which allow us to trace down instrumental errors, both systematic and accidental; (4) the only substantial and extant set of observations made with the torquetum, that is, a catalogue of 58 stars, compiled in Kassel in the years 1560–63.

Connecting the Scientific and Industrial Revolutions: The Role of Practical Mathematics

Disputes over whether the Scientific Revolution contributed to the Industrial Revolution begin with the common assumption that natural philosophers and artisans formed distinct groups. In reality, these groups merged together through a diverse group of applied mathematics teachers, textbook writers, and instrument makers catering to a market ranging from navigators and surveyors to bookkeepers. Besides its direct economic contribution in diffusing useful numerical skills, this “practical mathematics” facilitated later industrialization in two ways. First, a large supply of instrument and watch makers provided Britain with a pool of versatile, mechanically skilled labor to build the increasingly complicated machinery of the late eighteenth century. Second, the less well-known but equally revolutionary innovations in machine tools—which, contrary to the Habbakuk thesis, occurred largely in Britain during the 1820s and 1830s to mass-produce interchangeable parts for iron textile machinery—drew on a technology of exact measurement developed for navigational and astronomical instruments.

Little Lewis and Latin Folk in Chaucer's Prologue to the Treatise on the Astrolabe

Little Lewis and Latin Folk in Chaucer's Prologue to the <i>Treatise on the Astrolabe</i>

Mistar Kalender dalam Pengembangan Khazanah Instrument Falak

Calendars by humans are used to mark the change of days and dates. Basically the calendar refers to the movement of celestial bodies. For example, the Gregorian calendar is a calendar that refers to the movement of the Sun. At this point, actually knowing the date on the calendar can be through solar observations, but of course you need a tool. In this study trying to build a celestial instrument to determine the date on the Gregorian calendar called the Mistar Kalender. Furthermore, this study tries to analyze the extent of its accuracy as well as its advantages and disadvantages. This study uses a mixed method combining library and experimental methods with descriptive analysis and numerical analysis approaches where data collection is done through documentation and numerical experimental results. The result of this research is that the Calendar Ruler is built on the concept of the position of the Sun at the local celestial meridian by utilizing a stick/gnomon which will form a shadow length of different sunlight each day. The results of the numerical test carried out showed that the length of the gnomon affected the placement of the sign for the date. The disadvantage of this instrument is that it is local according to the coordinates of the place of observation and depends on the weather at the time of observation. The advantage is as a celestial education medium to make it easier to understand the concept of the Gregorian calendar from the position of the Sun when it is in the local sky meridian.Keywords: Calendar Ruler, Gnomon, Astronomical Instruments

Studi Analisis Akurasi Perhitungan Awal Waktu Shalat Menggunakan Universal Astrolabe

Universal Astrolabe is a type of Astrolabe that can be used in any region or latitude. This paper examines the accuracy of the Universal Astrolabe in determining the start of the five daily prayer times (Fajr, Zuhur, Asr, Maghrib and Isha). The purpose of this study was to determine the accuracy of the calculation method for determining the beginning of prayer times using the Universal Astrolabe. Astrolabe is one of the classical astronomical instruments that describes the celestial sphere in two dimensions and was originally used to determine the position of the Sun. Astrolabe comes from the Greek language which consists of the word "aster" which means star, and the word "labio" which means take, understand, and catch. In simple terms, Astrolabe can be interpreted as a tool to study the Stars. This instrument is a type of calculating tool. The function of the Astrolabe is very complex, namely to determine the position of the Sun or other stars, to determine the zodiac and its circulation scale, to determine the height of an object and determine solar time. The results showed that the method of calculating the initial prayer time applied in the Universal Astrolabe was the method of reading directly on the plate. The initial calculation of prayer times using the Universal Astrolabe results in a calculation difference between 0-3 minutes and the prayer time schedule set by the Ministry of Religion of the Republic of Indonesia, so it is considered quite accurate. This difference can be influenced by the diameter of the Universal Astrolabe and the accuracy of the reader when reading the curves and numbers listed on the Universal Astrolabe.Keywords: Prayer Times, Accuracy, Universal Astrolabe.

Special Section Guest Editorial: Extremely Large Telescopes

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.

Simulation of Radiative Transfer Within X-ray Microcalorimeter Absorbers

We present Monte Carlo simulations of radiative transfer within the absorbers of X-ray microcalorimeters, utilizing a numerical model for the photon propagation and photon absorption process within the absorber structure. In our model, we include effects of Compton scattering off bound electrons and fluorescence. Scattered or fluorescence photons as well as Auger and photoelectrons escaping the absorber can result in partial energy depositions. By implementing a simplified description of the physical processes compared to existing comprehensive particle transport software frameworks, our model aims to provide representative results at a small computational effort. This approach makes it possible to use our model for quick assessments, parametric studies, and application in other Monte Carlo-based instrument simulators like SIXTE, a software package for X-ray astronomical instrumentation. To study the impact of the energy loss effects on the spectral response of a microcalorimeter, we apply our model to the sensors of the cryogenic X-ray spectrometer X-IFU onboard the future Athena X-ray observatory.

Atmospheric Propagation Studies and Development of New Instrumentation for Astronomy, Radar, and Telecommunication Applications in the Subterahertz Frequency Range

Current progress in the development of new subterahertz instruments discussed in this paper, including antennas, high-power gyrotrons, and low-noise receivers, provides a wide range of possible applications. Atmospheric absorption has now become a major limitation in the application of such high-performance subTHz systems, and the choice of the optimal location of antennas for astronomical, radar, and communication systems is important. The latest results of studying the microwave astroclimate in northern Eurasia are presented. Based on these studies, new perspectives and corrected plans for installing new antennas at the Suffa Plateau and in the Caucasus are formulated, and possible applications of new instruments such as radars for locating space debris and communication hubs for deep space communications, which are based on extremely-high-power gyrotrons and low-noise superconducting receivers, are discussed.

Improving exoplanet detection power: Multivariate Gaussian process models for stellar activity

The radial velocity method is one of the most successful techniques for detecting exoplanets. It works by detecting the velocity of a host star, induced by the gravitational effect of an orbiting planet, specifically, the velocity along our line of sight which is called the radial velocity of the star. Low-mass planets typically cause their host star to move with radial velocities of 1 m/s or less. By analyzing a time series of stellar spectra from a host star, modern astronomical instruments can, in theory, detect such planets. However, in practice, intrinsic stellar variability (e.g., star spots, convective motion, pulsations) affects the spectra and often mimics a radial velocity signal. This signal contamination makes it difficult to reliably detect low-mass planets. A principled approach to recovering planet radial velocity signals in the presence of stellar activity was proposed by Rajpaul et al. (Mon. Not. R. Astron. Soc. 452 (2015) 2269–2291). It uses a multivariate Gaussian process model to jointly capture time series of the apparent radial velocity and multiple indicators of stellar activity. We build on this work in two ways: (i) we propose using dimension reduction techniques to construct new high-information stellar activity indicators; and (ii) we extend the Rajpaul et al. (Mon. Not. R. Astron. Soc. 452 (2015) 2269–2291) model to a larger class of models and use a power-based model comparison procedure to select the best model. Despite significant interest in exoplanets, previous efforts have not performed large-scale stellar activity model selection or attempted to evaluate models based on planet detection power. In the case of main sequence G2V stars, we find that our method substantially improves planet detection power, compared to previous state-of-the-art approaches.

Correlated Read Noise Reduction in Infrared Arrays Using Deep Learning

We present a new procedure rooted in deep learning to construct science images from data cubes collected by astronomical instruments using HxRG detectors in low-flux regimes. It improves on the drawbacks of the conventional algorithms to construct 2D images from multiple readouts by using the readout scheme of the detectors to reduce the impact of correlated readout noise. We train a convolutional recurrent neural network on simulated astrophysical scenes added to laboratory darks to estimate the flux on each pixel of science images. This method achieves a reduction of the noise on constructed science images when compared to standard flux-measurement schemes (correlated double sampling, up-the-ramp sampling), which results in a reduction of the error on the spectrum extracted from these science images. Over simulated data cubes created in a low signal-to-noise ratio regime where this method could have the largest impact, we find that the error on our constructed science images falls faster than a decay, and that the spectrum extracted from the images has, averaged over a test set of three images, a standard error reduced by a factor of 1.85 in comparison to the standard up-the-ramp pixel sampling scheme. The code used in this project is publicly available on GitHub 7 7 https://github.com/GuillaumePayeur/HxRG-denoiser

Development and characterization of a fast and low noise readout for the next generation x-ray charge-coupled devices

The broad energy response, low electronic read noise, and good energy resolution have made X-ray Charge-Coupled Devices (CCDs) an obvious choice for developing soft X-ray astronomical instruments over the last half century. They also come in large array formats with small pixel sizes which make them a potential candidate for the next generation astronomical X-ray missions. However, the next generation X-ray telescopic experiments propose for significantly larger collecting area compared to the existing observatories in order to explore the low luminosity and high redshift X-ray universe which requires these detectors to have an order of magnitude faster readout. In this context, the Stanford University (SU) in collaboration with the Massachusetts Institute of Technology (MIT) has initiated the development of fast readout electronics for X-ray CCDs. At SU, we have designed and developed a fast and low noise readout module with the goal of achieving a readout speed of 5 Mpixel/s. We successfully ran a prototype CCD matrix of 512 $\times$ 512 pixels at 4 Mpixels/s. In this paper, we describe the details of the readout electronics and report the performance of the detectors at these readout speeds in terms of read noise and energy resolution. In the future, we plan to continue to improve performance of the readout module and eventually converge to a dedicated ASIC based readout system to enable parallel read out of large array multi-node CCD devices.