Pub Date : 2021-08-07DOI: 10.13140/RG.2.2.12897.84322
Saurabh Gore, Manuel Ntumba
Lunar hematite is formed by the oxidation of iron on the surface of the Moon by oxygen from the Earth's upper atmosphere. The Moon's surface is continuously affected by solar particles from the sun. However, Earth's magnetic tail blocks 99 % of the solar wind and provides windows of opportunity to transport oxygen from Earth's upper atmosphere to the Moon through magnetotail when it is in its full moon phase. Here, we propose to place a space weather observatory at the Earth-Moon L1 Lagrange point carrying a crucial payload onboard to study how Earth's magnetotail causes the Moon's surface to rust. The space weather observatory monitors the effect of Earth's magnetic field on the Moon using advanced spectroscopic sensors from Lagrange-based stations. Earth-moon L1 Lagrange point is the key location for space-weather observation as spacecraft near this point obtains a nearly unobstructed view of the moon. Numerical methods needed for a high-order analytical approximation have been implemented for more accurate predictions.
{"title":"Space-based weather observatory at Earth-Moon Lagrange point L1 to monitor earth's magnetotail effects on the Moon","authors":"Saurabh Gore, Manuel Ntumba","doi":"10.13140/RG.2.2.12897.84322","DOIUrl":"https://doi.org/10.13140/RG.2.2.12897.84322","url":null,"abstract":"Lunar hematite is formed by the oxidation of iron on the surface of the Moon by oxygen from the Earth's upper atmosphere. The Moon's surface is continuously affected by solar particles from the sun. However, Earth's magnetic tail blocks 99 % of the solar wind and provides windows of opportunity to transport oxygen from Earth's upper atmosphere to the Moon through magnetotail when it is in its full moon phase. Here, we propose to place a space weather observatory at the Earth-Moon L1 Lagrange point carrying a crucial payload onboard to study how Earth's magnetotail causes the Moon's surface to rust. The space weather observatory monitors the effect of Earth's magnetic field on the Moon using advanced spectroscopic sensors from Lagrange-based stations. Earth-moon L1 Lagrange point is the key location for space-weather observation as spacecraft near this point obtains a nearly unobstructed view of the moon. Numerical methods needed for a high-order analytical approximation have been implemented for more accurate predictions.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89811563","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}
Wide field small aperture telescopes (WFSATs) are mainly used to obtain scientific information of point--like and streak--like celestial objects. However, qualities of images obtained by WFSATs are seriously affected by the background noise and variable point spread functions. Developing high speed and high efficiency data processing method is of great importance for further scientific research. In recent years, deep neural networks have been proposed for detection and classification of celestial objects and have shown better performance than classical methods. In this paper, we further extend abilities of the deep neural network based astronomical target detection framework to make it suitable for photometry and astrometry. We add new branches into the deep neural network to obtain types, magnitudes and positions of different celestial objects at the same time. Tested with simulated data, we find that our neural network has better performance in photometry than classical methods. Because photometry and astrometry are regression algorithms, which would obtain high accuracy measurements instead of rough classification results, the accuracy of photometry and astrometry results would be affected by different observation conditions. To solve this problem, we further propose to use reference stars to train our deep neural network with transfer learning strategy when observation conditions change. The photometry framework proposed in this paper could be used as an end--to--end quick data processing framework for WFSATs, which can further increase response speed and scientific outputs of WFSATs.
{"title":"The Deep Neural Network based Photometry Framework for Wide Field Small Aperture Telescopes.","authors":"J. Peng, Sun Yongyang, Liu Qiang","doi":"10.5281/ZENODO.4784689","DOIUrl":"https://doi.org/10.5281/ZENODO.4784689","url":null,"abstract":"Wide field small aperture telescopes (WFSATs) are mainly used to obtain scientific information of point--like and streak--like celestial objects. However, qualities of images obtained by WFSATs are seriously affected by the background noise and variable point spread functions. Developing high speed and high efficiency data processing method is of great importance for further scientific research. In recent years, deep neural networks have been proposed for detection and classification of celestial objects and have shown better performance than classical methods. In this paper, we further extend abilities of the deep neural network based astronomical target detection framework to make it suitable for photometry and astrometry. We add new branches into the deep neural network to obtain types, magnitudes and positions of different celestial objects at the same time. Tested with simulated data, we find that our neural network has better performance in photometry than classical methods. Because photometry and astrometry are regression algorithms, which would obtain high accuracy measurements instead of rough classification results, the accuracy of photometry and astrometry results would be affected by different observation conditions. To solve this problem, we further propose to use reference stars to train our deep neural network with transfer learning strategy when observation conditions change. The photometry framework proposed in this paper could be used as an end--to--end quick data processing framework for WFSATs, which can further increase response speed and scientific outputs of WFSATs.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80462305","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 : 2020-12-16DOI: 10.26119/978-5-6045062-0-2_2020_21
D. Kudryavtsev, V. Vlasyuk
The Russian 6-m telescope (BTA), once the largest telescope in the world and now the largest optical telescope in Russia, has been successfully operating for almost 45 years. In this paper we briefly overview the observing methods the facility can currently provide, the ongoing projects on the development of scientific equipment, the status of the telescope among the world's and Russian astronomical communities, our ambitions to attract new users, and the prospects the observatory wishes to realize in the near future.
{"title":"The Largest Russian Optical Telescope BTA: Current Status and Modernization Prospects","authors":"D. Kudryavtsev, V. Vlasyuk","doi":"10.26119/978-5-6045062-0-2_2020_21","DOIUrl":"https://doi.org/10.26119/978-5-6045062-0-2_2020_21","url":null,"abstract":"The Russian 6-m telescope (BTA), once the largest telescope in the world and now the largest optical telescope in Russia, has been successfully operating for almost 45 years. In this paper we briefly overview the observing methods the facility can currently provide, the ongoing projects on the development of scientific equipment, the status of the telescope among the world's and Russian astronomical communities, our ambitions to attract new users, and the prospects the observatory wishes to realize in the near future.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"12 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72596606","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}
A. Chen'e, S. Mao, M. Lundquist, E. Martioli, J. Carlin
This paper describes the software DRAGraces (Data Reduction and Analysis for GRACES), which is a pipeline reducing spectra from GRACES (Gemini Remote Access to the CFHT ESPaDOnS Spectrograph) at the Gemini North Telescope. The code is written in the IDL language. It is designed to find all the GRACES frames in a given directory, automatically determine the list of bias, flat, arc and science frames, and perform the whole reduction and extraction within a few minutes. We compare the output from DRAGraces with that of OPERA, a pipeline developed at CFHT that also can extract GRACES spectra. Both pipelines were developed completely independently, yet they give very similar extracted spectra. They both have their advantages and disadvantages. For instance, DRAGraces is more straightforward and easy to use and is less likely to be derailed by a parameter that needs to be tweaked, while OPERA offers a more careful extraction that can be significantly superior when the highest resolution is required and when the signal-to-noise ratio is low. One should compare both before deciding which one to use for their science. Yet, both pipelines deliver a fairly comparable resolution power (R~52.8k and 36.6k for DRAGraces and R~58k and 40k for OPERA in high and low-resolution spectral modes, respectively), wavelength solution and signal-to-noise ratio per resolution element.
本文介绍了一种名为DRAGraces (Data Reduction and Analysis for GRACES)的软件，它是一种对Gemini North望远镜上GRACES (Gemini Remote Access to the CFHT ESPaDOnS Spectrograph)的光谱进行管道化简的软件。代码是用IDL语言编写的。它能在给定的目录中找到所有的grace帧，自动确定bias、flat、arc和science帧的列表，并在几分钟内完成整个还原和提取。我们比较了DRAGraces和OPERA的输出，OPERA是CFHT开发的一个管道，也可以提取GRACES光谱。两种管道都是完全独立开发的，但它们给出了非常相似的提取光谱。他们都有各自的优点和缺点。例如，DRAGraces更直接，更容易使用，并且不太可能因需要调整的参数而偏离轨道，而OPERA提供了更仔细的提取，当需要最高分辨率和信噪比较低时，它可以显着优越。在决定用哪一种进行科学研究之前，人们应该对两者进行比较。然而，这两种管道的分辨率功率(在高分辨率和低分辨率光谱模式下，dragrace的分辨率分别为R~52.8k和36.6k, OPERA的分辨率分别为R~58k和40k)、波长解析度和每个分辨率元件的信噪比都相当。
{"title":"DRAGraces: A pipeline for the GRACES high-resolution spectrograph at Gemini.","authors":"A. Chen'e, S. Mao, M. Lundquist, E. Martioli, J. Carlin","doi":"10.5281/zenodo.2648829","DOIUrl":"https://doi.org/10.5281/zenodo.2648829","url":null,"abstract":"This paper describes the software DRAGraces (Data Reduction and Analysis for GRACES), which is a pipeline reducing spectra from GRACES (Gemini Remote Access to the CFHT ESPaDOnS Spectrograph) at the Gemini North Telescope. The code is written in the IDL language. It is designed to find all the GRACES frames in a given directory, automatically determine the list of bias, flat, arc and science frames, and perform the whole reduction and extraction within a few minutes. We compare the output from DRAGraces with that of OPERA, a pipeline developed at CFHT that also can extract GRACES spectra. Both pipelines were developed completely independently, yet they give very similar extracted spectra. They both have their advantages and disadvantages. For instance, DRAGraces is more straightforward and easy to use and is less likely to be derailed by a parameter that needs to be tweaked, while OPERA offers a more careful extraction that can be significantly superior when the highest resolution is required and when the signal-to-noise ratio is low. One should compare both before deciding which one to use for their science. Yet, both pipelines deliver a fairly comparable resolution power (R~52.8k and 36.6k for DRAGraces and R~58k and 40k for OPERA in high and low-resolution spectral modes, respectively), wavelength solution and signal-to-noise ratio per resolution element.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"126 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76703116","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 : 2020-12-03DOI: 10.1117/1.JATIS.7.2.021205
R. Hu, D. Lisman, S. Shaklan, Stefan R. Martin, P. Willems, K. Short
High-contrast imaging enabled by a starshade in formation flight with a space telescope can provide a near-term pathway to search for and characterize temperate and small planets of nearby stars. NASA's Starshade Technology Development Activity to TRL5 (S5) is rapidly maturing the required technologies to the point at which starshades could be integrated into potential future missions. Here we reappraise the noise budget of starshade-enabled exoplanet imaging to incorporate the experimentally demonstrated optical performance of the starshade and its optical edge. Our analyses of stray light sources - including the leakage through micrometeoroid damage and the reflection of bright celestial bodies - indicate that sunlight scattered by the optical edge (i.e., the solar glint) is by far the dominant stray light. With telescope and observation parameters that approximately correspond to Starshade Rendezvous with Roman and HabEx, we find that the dominating noise source would be exozodiacal light for characterizing a temperate and Earth-sized planet around Sun-like and earlier stars and the solar glint for later-type stars. Further reducing the brightness of solar glint by a factor of 10 with a coating would prevent it from becoming the dominant noise for both Roman and HabEx. With an instrument contrast of 1E-10, the residual starlight is not a dominant noise; and increasing the contrast level by a factor 10 would not lead to any appreciable change in the expected science performance. If unbiased calibration of the background to the photon-noise limit can be achieved, Starshade Rendezvous with Roman could provide nearly photon-limited spectroscopy of temperate and Earth-sized planets of F, G, and K stars <4 parsecs away, and HabEx could extend this capability to many more stars <8 parsecs. (Abridged)
{"title":"Overview and reassessment of noise budget of starshade exoplanet imaging","authors":"R. Hu, D. Lisman, S. Shaklan, Stefan R. Martin, P. Willems, K. Short","doi":"10.1117/1.JATIS.7.2.021205","DOIUrl":"https://doi.org/10.1117/1.JATIS.7.2.021205","url":null,"abstract":"High-contrast imaging enabled by a starshade in formation flight with a space telescope can provide a near-term pathway to search for and characterize temperate and small planets of nearby stars. NASA's Starshade Technology Development Activity to TRL5 (S5) is rapidly maturing the required technologies to the point at which starshades could be integrated into potential future missions. Here we reappraise the noise budget of starshade-enabled exoplanet imaging to incorporate the experimentally demonstrated optical performance of the starshade and its optical edge. Our analyses of stray light sources - including the leakage through micrometeoroid damage and the reflection of bright celestial bodies - indicate that sunlight scattered by the optical edge (i.e., the solar glint) is by far the dominant stray light. With telescope and observation parameters that approximately correspond to Starshade Rendezvous with Roman and HabEx, we find that the dominating noise source would be exozodiacal light for characterizing a temperate and Earth-sized planet around Sun-like and earlier stars and the solar glint for later-type stars. Further reducing the brightness of solar glint by a factor of 10 with a coating would prevent it from becoming the dominant noise for both Roman and HabEx. With an instrument contrast of 1E-10, the residual starlight is not a dominant noise; and increasing the contrast level by a factor 10 would not lead to any appreciable change in the expected science performance. If unbiased calibration of the background to the photon-noise limit can be achieved, Starshade Rendezvous with Roman could provide nearly photon-limited spectroscopy of temperate and Earth-sized planets of F, G, and K stars <4 parsecs away, and HabEx could extend this capability to many more stars <8 parsecs. (Abridged)","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"141 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78992500","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}
Metadata descriptions of Solar observations have so far only been standardized for space-based observations, but the standards have been mostly within a single space mission at a time, at times with significant differences between different mission standards. In the context of ground-based Solar observations, data has typically not been made freely available to the general research community, resulting in an even greater lack of standards for metadata descriptions. This situation makes it difficult to construct multi-instrument archives/virtual observatories with anything more than the most basic metadata available for searching, as well as making it difficult to write generic software for instrument-agnostic data analysis. This document describes the metadata recommendations developed under the SOLARNET EU project, which aims foster more collaboration and data sharing between both ground-based and space-based Solar observatories. The recommendations will be followed by data pipelines developed under the SOLARNET project as well as e.g. the Solar Orbiter SPICE pipeline and the SST CHROMIS/CRISP common pipeline. These recommendations are meant to function as a common reference to which even existing diverse data sets may be related, for ingestion into solar virtual observatories and for analysis by generic software.
{"title":"SOLARNET Metadata Recommendations for Solar Observations.","authors":"S. Haugan, T. Fredvik","doi":"10.5281/zenodo.5719255","DOIUrl":"https://doi.org/10.5281/zenodo.5719255","url":null,"abstract":"Metadata descriptions of Solar observations have so far only been standardized for space-based observations, but the standards have been mostly within a single space mission at a time, at times with significant differences between different mission standards. In the context of ground-based Solar observations, data has typically not been made freely available to the general research community, resulting in an even greater lack of standards for metadata descriptions. This situation makes it difficult to construct multi-instrument archives/virtual observatories with anything more than the most basic metadata available for searching, as well as making it difficult to write generic software for instrument-agnostic data analysis. This document describes the metadata recommendations developed under the SOLARNET EU project, which aims foster more collaboration and data sharing between both ground-based and space-based Solar observatories. The recommendations will be followed by data pipelines developed under the SOLARNET project as well as e.g. the Solar Orbiter SPICE pipeline and the SST CHROMIS/CRISP common pipeline. These recommendations are meant to function as a common reference to which even existing diverse data sets may be related, for ingestion into solar virtual observatories and for analysis by generic software.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78249442","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}
Junghwan Oh, J. Wagner, S. Trippe, Taeseok Lee, Bangwon Lee, Chang Hee Kim
Optical intensity interferometry, developed in the 1950s, is a simple and inexpensive method for achieving angular resolutions on microarcsecond scales. Its low sensitivity has limited intensity interferometric observations to bright stars so far. Substantial improvements are possible by using avalanche photodiodes (APDs) as light detectors. Several recent experiments used APDs in single-photon detection mode; however, these either provide low electronic bandwidths (few MHz) or require very narrow optical bandpasses. We present here the results of laboratory measurements with a prototype astronomical intensity interferometer using two APDs observing an artificial star in continuous ("linear") detection mode with an electronic bandwidth of 100~MHz. We find a photon--photon correlation of about $10^{-6}$, as expected from the ratio of the coherence times of the light source and the detectors. In a configuration where both detectors are on the optical axis (zero baseline), we achieve a signal-to-noise ratio of $sim$2700 after 10 minutes of integration. When measuring the correlation as a function of baseline, we find a Gaussian correlation profile with a standard deviation corresponding to an angular half-width of the artificial star of $0.55''$, in agreement with the estimate by the manufacturer. Our results demonstrate the possibility to construct large astronomical intensity interferometers using linear-mode APDs.
{"title":"Sirius: a prototype astronomical intensity interferometer using avalanche photodiodes in linear mode","authors":"Junghwan Oh, J. Wagner, S. Trippe, Taeseok Lee, Bangwon Lee, Chang Hee Kim","doi":"10.1093/mnras/staa3584","DOIUrl":"https://doi.org/10.1093/mnras/staa3584","url":null,"abstract":"Optical intensity interferometry, developed in the 1950s, is a simple and inexpensive method for achieving angular resolutions on microarcsecond scales. Its low sensitivity has limited intensity interferometric observations to bright stars so far. Substantial improvements are possible by using avalanche photodiodes (APDs) as light detectors. Several recent experiments used APDs in single-photon detection mode; however, these either provide low electronic bandwidths (few MHz) or require very narrow optical bandpasses. We present here the results of laboratory measurements with a prototype astronomical intensity interferometer using two APDs observing an artificial star in continuous (\"linear\") detection mode with an electronic bandwidth of 100~MHz. We find a photon--photon correlation of about $10^{-6}$, as expected from the ratio of the coherence times of the light source and the detectors. In a configuration where both detectors are on the optical axis (zero baseline), we achieve a signal-to-noise ratio of $sim$2700 after 10 minutes of integration. When measuring the correlation as a function of baseline, we find a Gaussian correlation profile with a standard deviation corresponding to an angular half-width of the artificial star of $0.55''$, in agreement with the estimate by the manufacturer. Our results demonstrate the possibility to construct large astronomical intensity interferometers using linear-mode APDs.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"16 61","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91423545","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 : 2020-11-17DOI: 10.3847/25C2CFEB.F3D901D1
P. Horzempa
A Viking-class Europa Lander is a high-risk, high-cost venture. In its place, Europa should be explored by a series of low-cost scouts. These will be landers and small flyby craft. These missions will ascertain the nature of Europa's surface at a scale of meters to centimeters. Some will search for the presence of organic molecules. All of them will precede a large Europa Lander.
{"title":"Europa Exploration Philosophy","authors":"P. Horzempa","doi":"10.3847/25C2CFEB.F3D901D1","DOIUrl":"https://doi.org/10.3847/25C2CFEB.F3D901D1","url":null,"abstract":"A Viking-class Europa Lander is a high-risk, high-cost venture. In its place, Europa should be explored by a series of low-cost scouts. These will be landers and small flyby craft. These missions will ascertain the nature of Europa's surface at a scale of meters to centimeters. Some will search for the presence of organic molecules. All of them will precede a large Europa Lander.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77848315","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}
RF system-on-chip (RFSoC) devices provide the potential for implementing a complete radio astronomy receiver on a single board, but performance of the integrated analogue-to-digital converters is critical. We have evaluated the performance of the data converters in the Xilinx ZU28DR RFSoC, which are 12-bit, 8-fold interleaved converters with a maximum sample speed of 4.096 Giga-sample per second (GSPS). We measured the spurious-free dynamic range (SFDR), signal-to-noise and distortion (SINAD), effective number of bits (ENOB), intermodulation distortion (IMD) and cross-talk between adjacent channels over the bandwidth of 2.048 GHz. We both captured data for off-line analysis with floating-point arithmetic, and implemented a real-time integer arithmetic spectrometer on the RFSoC. The performance of the ADCs is sufficient for radio astronomy applications and close to the vendor specifications in most of the scenarios. We have carried out spectral integrations of up to 100 s and stability tests over tens of hours and find thermal noise-limited performance over these timescales.
{"title":"Characterizing the performance of high-speed data converters for RFSoC-based radio astronomy receivers","authors":"Chao Liu, Michael E. Jones, A. Taylor","doi":"10.1093/mnras/staa3895","DOIUrl":"https://doi.org/10.1093/mnras/staa3895","url":null,"abstract":"RF system-on-chip (RFSoC) devices provide the potential for implementing a complete radio astronomy receiver on a single board, but performance of the integrated analogue-to-digital converters is critical. We have evaluated the performance of the data converters in the Xilinx ZU28DR RFSoC, which are 12-bit, 8-fold interleaved converters with a maximum sample speed of 4.096 Giga-sample per second (GSPS). We measured the spurious-free dynamic range (SFDR), signal-to-noise and distortion (SINAD), effective number of bits (ENOB), intermodulation distortion (IMD) and cross-talk between adjacent channels over the bandwidth of 2.048 GHz. We both captured data for off-line analysis with floating-point arithmetic, and implemented a real-time integer arithmetic spectrometer on the RFSoC. The performance of the ADCs is sufficient for radio astronomy applications and close to the vendor specifications in most of the scenarios. We have carried out spectral integrations of up to 100 s and stability tests over tens of hours and find thermal noise-limited performance over these timescales.","PeriodicalId":8459,"journal":{"name":"arXiv: Instrumentation and Methods for Astrophysics","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85648686","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 : 2020-11-09DOI: 10.1117/1.JATIS.7.2.021207
A. Harness, S. Shaklan, P. Willems, N. Kasdin, K. Balasubramanian, P. Dumont, V. White, K. Yee, R. Muller, Michael B. Galvin
Starshades are a leading technology to enable the detection and spectroscopic characterization of Earth-like exoplanets. In this paper we report on optical experiments of sub-scale starshades that advance critical starlight suppression technologies in preparation for the next generation of space telescopes. These experiments were conducted at the Princeton starshade testbed, an 80 m long enclosure testing 1/1000th scale starshades at a flight-like Fresnel number. We demonstrate 1e-10 contrast at the starshade's geometric inner working angle across 10% of the visible spectrum, with an average contrast at the inner working angle of 2.0e-10 and contrast floor of 2e-11. In addition to these high contrast demonstrations, we validate diffraction models to better than 35% accuracy through tests of intentionally flawed starshades. Overall, this suite of experiments reveals a deviation from scalar diffraction theory due to light propagating through narrow gaps between the starshade petals. We provide a model that accurately captures this effect at contrast levels below 1e-10. The results of these experiments demonstrate that there are no optical impediments to building a starshade that provides sufficient contrast to detect Earth-like exoplanets. This work also sets an upper limit on the effect of unknowns in the diffraction model used to predict starshade performance and set tolerances on the starshade manufacture.
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