Pub Date : 2021-08-23DOI: 10.1142/s2251171722500027
Sasha R. Brownsberger, Lige Zhang, D. Andrade, Christopher Stubbs
As the precision frontier of astrophysics advances toward the one millimagnitude level, flux calibration of photometric instrumentation remains an ongoing challenge. We present the results of a lab-bench assessment of the viability of monocrystalline silicon solar cells to serve as large-aperture (up to 125[Formula: see text]mm diameter), high-precision photodetectors. We measure the electrical properties, spatial response uniformity, quantum efficiency (QE), and frequency response of third-generation C60 solar cells, manufactured by Sunpower. Our new results, combined with our previous study of these cells’ linearity, dark current, and noise characteristics, suggest that these devices hold considerable promise, with QE and linearity that rival those of traditional, small-aperture photodiodes. We argue that any photocalibration project that relies on precise knowledge of the intensity of a large-diameter optical beam should consider using solar cells as calibrating photodetectors.
{"title":"Characterization and Quantum Efficiency Determination of Monocrystalline Silicon Solar Cells as Sensors for Precise Flux Calibration","authors":"Sasha R. Brownsberger, Lige Zhang, D. Andrade, Christopher Stubbs","doi":"10.1142/s2251171722500027","DOIUrl":"https://doi.org/10.1142/s2251171722500027","url":null,"abstract":"As the precision frontier of astrophysics advances toward the one millimagnitude level, flux calibration of photometric instrumentation remains an ongoing challenge. We present the results of a lab-bench assessment of the viability of monocrystalline silicon solar cells to serve as large-aperture (up to 125[Formula: see text]mm diameter), high-precision photodetectors. We measure the electrical properties, spatial response uniformity, quantum efficiency (QE), and frequency response of third-generation C60 solar cells, manufactured by Sunpower. Our new results, combined with our previous study of these cells’ linearity, dark current, and noise characteristics, suggest that these devices hold considerable promise, with QE and linearity that rival those of traditional, small-aperture photodiodes. We argue that any photocalibration project that relies on precise knowledge of the intensity of a large-diameter optical beam should consider using solar cells as calibrating photodetectors.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42914173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-08-10DOI: 10.1142/s2251171721500161
Jeffrey R. Swaney, C. Shimmin, D. Whiteson
A scientific instrument comprised of a global network of millions of independent, connected, remote devices presents unique data acquisition challenges. We describe the software design of a mobile application which collects data from smartphone cameras without overburdening the phone's CPU or battery. The deployed software automatically calibrates to heterogeneous hardware targets to improve the quality and manage the rate of data transfer, and connects to a cloud-based data acquisition system which can manage and refine the operation of the network.
{"title":"Data Acquisition System for a Distributed Smartphone Cosmic Ray Observatory","authors":"Jeffrey R. Swaney, C. Shimmin, D. Whiteson","doi":"10.1142/s2251171721500161","DOIUrl":"https://doi.org/10.1142/s2251171721500161","url":null,"abstract":"A scientific instrument comprised of a global network of millions of independent, connected, remote devices presents unique data acquisition challenges. We describe the software design of a mobile application which collects data from smartphone cameras without overburdening the phone's CPU or battery. The deployed software automatically calibrates to heterogeneous hardware targets to improve the quality and manage the rate of data transfer, and connects to a cloud-based data acquisition system which can manage and refine the operation of the network.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43461329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-07-09DOI: 10.1142/s2251171721500124
I. Helmy, A. Hamdy, Doaa Eid, A. Shokry
Focus accuracy affects the quality of the astronomical observations. Auto-focusing is necessary for imaging systems designed for astronomical observations. The automatic focus system searches for the best focus position by using a proposed search algorithm. The search algorithm uses the image’s focus levels as its objective function in the search process. This paper aims to study the performance of several search algorithms to select a suitable one. The proper search algorithm will be used to develop an automatic focus system for Kottamia Astronomical Observatory (KAO). The optimal search algorithm is selected by applying several search algorithms into five sequences of star-clusters observations. Then, their performance is evaluated based on two criteria, which are accuracy and number of steps. The experimental results show that the Binary search is the optimal search algorithm.
{"title":"Autofocusing Optimal Search Algorithm for a Telescope System","authors":"I. Helmy, A. Hamdy, Doaa Eid, A. Shokry","doi":"10.1142/s2251171721500124","DOIUrl":"https://doi.org/10.1142/s2251171721500124","url":null,"abstract":"Focus accuracy affects the quality of the astronomical observations. Auto-focusing is necessary for imaging systems designed for astronomical observations. The automatic focus system searches for the best focus position by using a proposed search algorithm. The search algorithm uses the image’s focus levels as its objective function in the search process. This paper aims to study the performance of several search algorithms to select a suitable one. The proper search algorithm will be used to develop an automatic focus system for Kottamia Astronomical Observatory (KAO). The optimal search algorithm is selected by applying several search algorithms into five sequences of star-clusters observations. Then, their performance is evaluated based on two criteria, which are accuracy and number of steps. The experimental results show that the Binary search is the optimal search algorithm.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2021-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42422119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-11DOI: 10.1142/S2251171721500070
T. Dyson, H. Chiang, E. Egan, N. Ghazi, T. Menard, R. Monsalve, T. Moso, J. Peterson, J. Sievers, S. Tartakovsky
The frequencies of interest for redshifted 21[Formula: see text]cm observations are heavily affected by terrestrial radio-frequency interference (RFI). We identify the McGill Arctic Research Station (MARS) as a new RFI-quiet site and report its RFI occupancy using 122[Formula: see text]h of data taken with a prototype antenna station developed for the Array of Long-Baseline Antennas for Taking Radio Observations from the Sub-Antarctic. Using an RFI flagging process tailored to the MARS data, we find an overall RFI occupancy of 1.8% averaged over 20–125[Formula: see text]MHz. In particular, the FM broadcast band (88–108[Formula: see text]MHz) is found to have an RFI occupancy of at most 1.6%. The data were taken during the Arctic summer, when degraded ionospheric conditions and an active research base contributed to increased RFI. The results quoted here therefore represent the maximum-level RFI environment at MARS.
{"title":"Radio-Frequency Interference at the McGill Arctic Research Station","authors":"T. Dyson, H. Chiang, E. Egan, N. Ghazi, T. Menard, R. Monsalve, T. Moso, J. Peterson, J. Sievers, S. Tartakovsky","doi":"10.1142/S2251171721500070","DOIUrl":"https://doi.org/10.1142/S2251171721500070","url":null,"abstract":"The frequencies of interest for redshifted 21[Formula: see text]cm observations are heavily affected by terrestrial radio-frequency interference (RFI). We identify the McGill Arctic Research Station (MARS) as a new RFI-quiet site and report its RFI occupancy using 122[Formula: see text]h of data taken with a prototype antenna station developed for the Array of Long-Baseline Antennas for Taking Radio Observations from the Sub-Antarctic. Using an RFI flagging process tailored to the MARS data, we find an overall RFI occupancy of 1.8% averaged over 20–125[Formula: see text]MHz. In particular, the FM broadcast band (88–108[Formula: see text]MHz) is found to have an RFI occupancy of at most 1.6%. The data were taken during the Arctic summer, when degraded ionospheric conditions and an active research base contributed to increased RFI. The results quoted here therefore represent the maximum-level RFI environment at MARS.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2020-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46610365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-07-14DOI: 10.1142/S2251171721500021
I. Loutsenko, O. Yermolayeva
We propose a class of graded coronagraphic “amplitude” image masks for a high throughput Lyot-type coronagraph that transmits light from an annular region around an extended source and suppresses light, with extremely high ratio, from elsewhere. The interior radius of the region is comparable with its exterior radius. The masks are designed using an idea inspired by approach due M. J. Kuchner and W. A. Traub (“band-limited” masks) and approach to optimal apodization by D. Slepian. One potential application of our masks is direct high-resolution imaging of exo-planets with the help of the Solar Gravitational Lens, where apparent radius of the “Einstein ring” image of a planet is of the order of an arc-second and is comparable with the apparent radius of the sun and solar corona.
我们提出了一类梯度日冕“振幅”图像掩模，用于高通量lyot型日冕仪，该日冕仪传输来自扩展光源周围环状区域的光，并以极高的比例抑制来自其他地方的光。区域的内部半径与其外部半径相当。口罩的设计灵感来自于M. J. Kuchner和W. A. Traub(“带限制”口罩)的方法和D. Slepian的最佳化方法。我们的掩模的一个潜在应用是在太阳引力透镜的帮助下直接对系外行星进行高分辨率成像，其中行星的“爱因斯坦环”图像的视半径是一弧秒的数量级，与太阳和日冕的视半径相当。
{"title":"Quasi-Band-Limited Coronagraph for Extended Sources","authors":"I. Loutsenko, O. Yermolayeva","doi":"10.1142/S2251171721500021","DOIUrl":"https://doi.org/10.1142/S2251171721500021","url":null,"abstract":"We propose a class of graded coronagraphic “amplitude” image masks for a high throughput Lyot-type coronagraph that transmits light from an annular region around an extended source and suppresses light, with extremely high ratio, from elsewhere. The interior radius of the region is comparable with its exterior radius. The masks are designed using an idea inspired by approach due M. J. Kuchner and W. A. Traub (“band-limited” masks) and approach to optimal apodization by D. Slepian. One potential application of our masks is direct high-resolution imaging of exo-planets with the help of the Solar Gravitational Lens, where apparent radius of the “Einstein ring” image of a planet is of the order of an arc-second and is comparable with the apparent radius of the sun and solar corona.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2020-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41766330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-26DOI: 10.1142/s2251171720500038
D. Cutajar, A. Magro, J. Borg, Kris Zarb Adami, G. Bianchi, G. Pupillo, A. Mattana, G. Naldi, C. Bortolotti, F. Perini, L. Lama, M. Schiaffino, M. Roma, A. Maccaferri, P. Lizia, M. Massari, M. Losacco
The growing population of artificial satellites in near-Earth orbit has made the monitoring of orbital debris objects ever more important. Orbital debris objects pose a threat to these satellites as their orbit cannot be changed in order to avoid a collision. In recent years, the European Space Agency (ESA)’s Space Surveillance and Tracking (SST) programme has been assisting national institutions in the upgrading of their space debris detection and monitoring capabilities. One of the latest such systems within this programme is the BIRALES space surveillance system based in Italy. The receiving antenna is a radio telescope that is made up of 32 receivers which are placed on eight parabolic cylindrical reflectors of the North–South arm of the Istituto Nazionale di Astrofisica (INAF)’s Northern Cross. This work introduces a new software backend which was developed for this novel space debris sensor. The system was designed to be a fast, highly configurable software backend for the radio telescope’s acquisition and processing system and whose monitoring and control can be realized by a simple front-end web-based application. The real-time detection of Resident Space Object (RSO) is an important prerequisite for such a system as it gives the operator an immediate feedback loop on any detections whilst keeping the storage requirements at a minimum given that there is no need to save the raw data. The detection of high-velocity objects is achieved by means of a specially developed data processing pipeline that uses the received raw antenna voltages to generate a number of beams, collectively known as a multipixel, that cover the Field of View (FoV) of the instrument. The trajectory of the detected objects is determined by considering the illumination sequence within this multipixel. The initial results on known objects represent the first steps in extending the growing network of European SST systems.
{"title":"PyBIRALES: A Radar Data Processing Backend for the Real-Time Detection of Space Debris","authors":"D. Cutajar, A. Magro, J. Borg, Kris Zarb Adami, G. Bianchi, G. Pupillo, A. Mattana, G. Naldi, C. Bortolotti, F. Perini, L. Lama, M. Schiaffino, M. Roma, A. Maccaferri, P. Lizia, M. Massari, M. Losacco","doi":"10.1142/s2251171720500038","DOIUrl":"https://doi.org/10.1142/s2251171720500038","url":null,"abstract":"The growing population of artificial satellites in near-Earth orbit has made the monitoring of orbital debris objects ever more important. Orbital debris objects pose a threat to these satellites as their orbit cannot be changed in order to avoid a collision. In recent years, the European Space Agency (ESA)’s Space Surveillance and Tracking (SST) programme has been assisting national institutions in the upgrading of their space debris detection and monitoring capabilities. One of the latest such systems within this programme is the BIRALES space surveillance system based in Italy. The receiving antenna is a radio telescope that is made up of 32 receivers which are placed on eight parabolic cylindrical reflectors of the North–South arm of the Istituto Nazionale di Astrofisica (INAF)’s Northern Cross. This work introduces a new software backend which was developed for this novel space debris sensor. The system was designed to be a fast, highly configurable software backend for the radio telescope’s acquisition and processing system and whose monitoring and control can be realized by a simple front-end web-based application. The real-time detection of Resident Space Object (RSO) is an important prerequisite for such a system as it gives the operator an immediate feedback loop on any detections whilst keeping the storage requirements at a minimum given that there is no need to save the raw data. The detection of high-velocity objects is achieved by means of a specially developed data processing pipeline that uses the received raw antenna voltages to generate a number of beams, collectively known as a multipixel, that cover the Field of View (FoV) of the instrument. The trajectory of the detected objects is determined by considering the illumination sequence within this multipixel. The initial results on known objects represent the first steps in extending the growing network of European SST systems.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2020-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/s2251171720500038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44570733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-01DOI: 10.1142/S2251171720500087
C. Dilullo, G. Taylor, J. Dowell
The search for the spectral signature of hydrogen from the formation of the first stars, known as Cosmic Dawn or First Light, is an ongoing effort around the world. The signature should present itself as a decrease in the temperature of the 21[Formula: see text]cm transition relative to that of the Cosmic Microwave Background and is believed to reside somewhere below 100[Formula: see text]MHz. A potential detection was published by the Experiment to Detect the Global EoR Signal (EDGES) collaboration with a profile centered around 78[Formula: see text]MHz of both unexpected depth and width (Bowman et al. [2018] Nature 555, 67). If validated, this detection will have profound impacts on the current paradigm of structure formation within [Formula: see text]CDM cosmology. We present an attempt to detect the spectral signature reported by the EDGES collaboration with the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA-SV). LWA-SV differs from other instruments in that it is a 256 element antenna array and offers beamforming capabilisties that should help with calibration and detection. We report first limits from LWA-SV and look toward future plans to improve these limits.
{"title":"Using the Long Wavelength Array to Search for Cosmic Dawn","authors":"C. Dilullo, G. Taylor, J. Dowell","doi":"10.1142/S2251171720500087","DOIUrl":"https://doi.org/10.1142/S2251171720500087","url":null,"abstract":"The search for the spectral signature of hydrogen from the formation of the first stars, known as Cosmic Dawn or First Light, is an ongoing effort around the world. The signature should present itself as a decrease in the temperature of the 21[Formula: see text]cm transition relative to that of the Cosmic Microwave Background and is believed to reside somewhere below 100[Formula: see text]MHz. A potential detection was published by the Experiment to Detect the Global EoR Signal (EDGES) collaboration with a profile centered around 78[Formula: see text]MHz of both unexpected depth and width (Bowman et al. [2018] Nature 555, 67). If validated, this detection will have profound impacts on the current paradigm of structure formation within [Formula: see text]CDM cosmology. We present an attempt to detect the spectral signature reported by the EDGES collaboration with the Long Wavelength Array station located on the Sevilleta National Wildlife Refuge in New Mexico, USA (LWA-SV). LWA-SV differs from other instruments in that it is a 256 element antenna array and offers beamforming capabilisties that should help with calibration and detection. We report first limits from LWA-SV and look toward future plans to improve these limits.","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1142/S2251171720500087","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43829657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1142/S2251171719800023
A. Stark
{"title":"Book Review: \"Radio Telescope Reflectors: Historical Development of Design and Construction by Jacob W. M. Baars and Hans J. Kärcher\"","authors":"A. Stark","doi":"10.1142/S2251171719800023","DOIUrl":"https://doi.org/10.1142/S2251171719800023","url":null,"abstract":"","PeriodicalId":45132,"journal":{"name":"Journal of Astronomical Instrumentation","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44077787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：