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1.
AST3-2 (the second Antarctic Survey Telescope) is located in Antarctic Dome A, the loftiest ice dome on the Antarctic Plateau. It produces a huge amount of observational data which require a more efficient data reduction program to be developed. Also the data transmission in Antarctica is much difficult, thus it is necessary to perform data reduction and detect variable and transient sources remotely and automatically in Antarctica, but this attempt is restricted by the unsatisfactory performance of the low power consumption computer in Antarctica. For realizing this purpose, to develop a new method based on the existing image subtraction method and random forest algorithm, taking the AST3-2 2016 dataset as the test sample, becomes an alternative choice. This method performs image subtraction on the dataset, then applies the principle component analysis to extract the features of residual images. Random forest is used as a machine learning classifier, and in the test a recall rate of 97% is resulted for the positive sample. Our work has verified the feasibility and accuracy of this method, and finally found out a batch of candidates for variable stars in the AST3-2 2016 dataset.  相似文献   

2.
Antarctic Survey Telescopes(AST3) are designed to be fully robotic telescopes at Dome A,Antarctica,which aim for highly efficient time-domain sky surveys as well as rapid response to special transient events(e.g.,gamma-ray bursts,near-Earth asteroids,supernovae,etc.).Unlike traditional observations,a well-designed real-time survey scheduler is needed in order to implement an automatic survey in a very efficient,reliable and flexible way for the unattended telescopes.We present a study of the survey strategy for AST3 and implementation of its survey scheduler,which is also useful for other survey projects.  相似文献   

3.
COCHISE (Cosmological Observations at Concordia with High-sensitivity Instrument for Source Extraction) is a 2.6 m telescope located on the high Antarctic Plateau near the Italian–French Concordia Base. The telescope is mainly devoted to Cosmological observations, able to operate between 200 μm and 3 mm of wavelength. In this paper we describe the main characteristics of the instrument. We also report on the first light, obtained during summer 2010–2011: this result marks the beginning of millimetre astrophysical observations at Concordia. Responsivity, noise equivalent temperature and field of view of the instrument are reported. At present COCHISE is the largest telescope located at Concordia. Beside the scientific expectations, the use of this kind of instrument in the Antarctic environment poses technological aspects of relevant interest: thus COCHISE can be considered as a pathfinder for future Antarctic telescopes.  相似文献   

4.
Due to its wide wavelength coverage, multi-resolution mode, and high transmission efficiency, the wide field multi-object spectrograph becomes the most common-used universal instrument in extremely large telescopes. It's still a great challenge to build the wide field multi-object spectrograph for a 30 m class telescope because of its sharply increased volume and budget. With the rapid development of astronomy and astrophysics, the innovation of astronomical technology is fundamentally required. In this paper, the research progress of different kinds of wide-field multi-object spectrographs is illustrated and reviewed, the recent status of conceptual designs and the instrument features of the wide field multi-object spectrographs of the three 30 m class telescopes in the world, especially the current effort made by the Chinese team for the wide field multi-object spectrograph of the Thirty Meter Telescope (TMT) are introduced.  相似文献   

5.
The HEGRA-collaboration is operating a system of imaging atmospheric Cherenkov telescopes to search for sources of TeV-γ-rays. Air showers are observed in stereoscopic mode with several telescopes simultaneously. To trigger the telescope system a versatile two-level trigger scheme has been implemented, which allows a significant reduction of the energy threshold with respect to single telescopes. The technical implementation of this trigger scheme and the performance of the trigger system are described. Results include the dependence of single- and multi-telescope trigger rates on the trigger thresholds, on the orientation of the telescopes, and on the type of the primary particle.  相似文献   

6.
Cherenkov telescopes have the capability of detecting high energy tau neutrinos in the energy range of 1–1000 PeV by searching for very inclined showers. If a tau lepton, produced by a tau neutrino, escapes from the Earth or a mountain, it will decay and initiate a shower in the air which can be detected by an air shower fluorescence or Cherenkov telescope. In this paper, we present detailed Monte Carlo simulations of corresponding event rates for the VERITAS and two proposed Cherenkov Telescope Array sites: Meteor Crater and Yavapai Ranch, which use representative AGN neutrino flux models and take into account topographic conditions of the detector sites. The calculated neutrino sensitivities depend on the observation time and the shape of the energy spectrum, but in some cases are comparable or even better than corresponding neutrino sensitivities of the IceCube detector. For VERITAS and the considered Cherenkov Telescope Array sites the expected neutrino sensitivities are up to factor 3 higher than for the MAGIC site because of the presence of surrounding mountains.  相似文献   

7.
Over the next several years we will deploy a series of spectrometers, imagers, and telescopes at the South Pole as part of a project named SPIREX-for South Pole Infrared Explorer. Our goal is to survey a substantial area of the sky to study the origins of galaxies and stars.From space, the zodiacal light is the limiting source of noise over a wide range of wavelengths. It has a minimum in the near infrared: the reflected sunlight is diminishing with wavelength and reradiated thermal emission from the warm dust is on the rise. For this and other reasons, the near infrared is potentially the best window in which to carry out deep surveys of galaxies.On the ground, the sensitivity of observations in the near infrared is limited by the Poisson noise of the large background flux from the atmosphere and telescope. Within a restricted wavelength range, this background depends only on two parameters: their temperature and emissivity. By building very low emissivity telescopes and operating them in the bitter cold of the Antarctic winter we expect to make observations that will rival in sensitivity those attainable from cooled space-based telescopes.  相似文献   

8.
The International Space Station offers a unique platform for rapid and inexpensive deployment of space telescopes. A scientific opportunity of great potential later this decade is the use of telescopes for the electromagnetic follow-up of ground-based gravitational wave detections of neutron star and black hole mergers. We describe this possibility for OpTIIX, an ISS technology demonstration of a 1.5 m diffraction limited optical telescope assembled in space, and ISS-Lobster, a wide-field imaging X-ray telescope now under study as a potential NASA mission. Both telescopes will be mounted on pointing platforms, allowing rapid positioning to the source of a gravitational wave event. Electromagnetic follow-up rates of several per year appear likely, offering a wealth of complementary science on the mergers of black holes and neutron stars.  相似文献   

9.
Recent studies have demonstrated that detailed monitoring of gravitational microlensing events can reveal the presence of planets orbiting the microlensed source stars. With the potential of probing planets in the Galactic bulge and Magellanic Clouds, such detections greatly increase the volume over which planets can be found. This paper expands on the original studies by considering the effect of planetary phase on the form of the resultant microlensing light curve. It is found that crescent-like sources can undergo substantially more magnification than a uniformly illuminated disc, the model typically employed in studying such planets. In fact, such a circularly symmetric model is found to suffer a minimal degree of magnification when compared with the crescent models. The degree of magnification is also a strong function of the planet's orientation with respect to the microlensing caustic. The form of the magnification variability is strongly dependent on the planetary phase and from which direction the planet is swept by the caustic, providing further clues to the geometry of the planetary system. As the amount of light reflected from a planet also depends on its phase, the detection of extreme crescent-like planets requires the advent of 30-m class telescopes, while light curves of planets at more moderate phases can be determined with today's 10-m telescopes.  相似文献   

10.
This article reviews the situation for robotization of telescopes and instruments at the Antarctic station Concordia on Dome C. A brain‐storming meeting was held in Tenerife in March 2007 from which this review emerged.We describe and summarize the challenges for night‐time operations of various astronomical experiments at conditions “between Earth and Space” and conclude that robotization is likely a prerequisite for continuous astronomical data taking during the 2000‐hour night at Dome C. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

11.
天文光学望远镜轴系驱动方式发展概述   总被引：4，自引：0，他引：4  
王国民 《天文学进展》2007,25(4):364-374
该文首先介绍了已投入使用的2.5米口径以上的25架地平式光学望远镜和11架赤道式光学望远镜轴系驱动方式,并概述了天文光学望远镜轴系驱动及其相关技术的发展过程;然后对目前国际上在研的6架大型光学望远镜和预研的10架极大光学望远镜轴系所采用的驱动形式进行了归类;最后分析了未来极大光学望远镜轴系驱动的发展趋势和与之相关的研究内容.  相似文献   

12.
After considering a number of historical but somewhat “forgotten” UV astronomy experiments, I discuss a number of ways of non-conventional astronomy in the ultraviolet that, on first considerations, could be viable alternatives and valuable complements to classical space observations. These are (a) UV astronomy from the Antarctic or the Arctic regions that take advantage of the “ozone hole”, (b) the use of high-altitude stratospheric balloon-borne telescopes, and (c) the operation of UV telescopes on the Moon. The advantages of these options are discussed and evaluated against the costs of each option and, one by one, are mostly rejected as not fully justifying the specific alternative. The possibility to achieve valuable (but limited) UV science, such as imaging at ～2000 Å, using long-duration stratospheric balloons is described. The option of lunar UV observatories is retained to be implemented for the case of a UV interferometer, where the stability of the lunar regolith is seen as a significant advantage in comparison to free-flying interferometers. A location beyond the main asteroid belt, where the background due zodiacal light may be negligible, is advocated as an ideal location for a UV observatory in the Solar System.  相似文献   

13.
This paper reviews positioning systems in the context of communication systems.First,the basic positioning technique is described for location based service(LBS) in mobile communication systems.Then the high integrity global positioning system(iGPS) is introduced in terms of aspects of what it is and how the low Earth orbit(LEO) Iridium telecommunication satellites enhance the global positioning system(GPS).Emphasis is on the Chinese Area Positioning System(CAPS) which is mainly based on commercial geostationary(GEO) communication satellites,including decommissioned GEO and inclined geosynchronous communication satellites.Characterized by its low cost,high flexibility,wide-area coverage and ample frequency resources,a distinctive feature of CAPS is that its navigation messages are generated on the ground,then uploaded to and forwarded by the communication satellites.Fundamental principles and key technologies applied in the construction of CAPS are presented in detail from the CAPS validation phase to its experimental system setup.A prospective view of CAPS has concluded it to be a seamless,high accuracy,large capacity navigation and communication system which can be achieved by expanding it world wide and enhancing it with LEO satellites and mobile base stations.Hence,this system is a potential candidate for the next generation of radio navigation after GPS.  相似文献   

14.
In this exploratory simulation study, we compare the event-progenitor classification potential of a variety of measurable parameters of atmospheric Cherenkov pulses which are produced by ultrahigh energy γ-ray and hadron progenitors and are likely to be recorded by the TACTIC (TeV atmospheric Cherenkov telescope with imaging camera) array of atmospheric Cherenkov telescopes. The parameters derived from Cherenkov images include Hillas, fractal and wavelet moments, while those obtained from non-image Cherenkov data consist of pulse profile rise time and base width and the relative ultraviolet to visible light content of the Cherenkov event. It is shown by a neural-net approach that these parameters, when used in suitable combinations, can bring about a proper segregation of the two event types, even with modest sized data samples of progenitor particles.  相似文献   

15.
J.W.V.Storey 《天文学报》2006,47(4):407-409
南极洲高原的天文开发在过去的10年中有了显著的进展．大的天文设施已在南极(South Pole)的Amundsen-Scott站运行,更具威力的望远镜已在计划或正在那儿建设,然而由于一些重要的原因,高原站址冰穹A(Dome A)和冰穹C(Dome C)对多种天文学科似乎比南极更具有利条件．2005年1月中国对冰穹A的成功考察,加上2005年以整年运行为目的的法/意Concordia站在冰穹C的开启,已为南极洲天文学创造了激动人心的新机遇．  相似文献   

16.
硬X射线能带 (2 0KeV～ 1MeV)是我们了解天体物理中高能辐射过程的一个好窗口。成像硬X射线望远镜可以提供更好的分辨率和灵敏度来研究硬X射线天体物理学。本文介绍了成像硬X射线望远镜在美国和欧洲的发展 ,这包括 :1 )EXITE2 ,由美国哈佛———史密松林天体物理中心设计和运行的一个光电开关成像硬X射线望远镜 ;2 )EXIST ,一个成像硬X射线全天巡天望远镜 ,将于 2 0 1 0年由ULDB (EXIST -LINE)或国际空间站 (EXIST -ISS)承载 ;3)HERO ,由NASA/MSFC建造的一个新的硬X射线光学仪器。  相似文献   

17.
Abstract— The nonmagnetic separates of Antarctic H- and L-chondrite finds from the Lewis Cliff stranding area are enriched in Fe and siderophile elements such as Ni, Co, Cu, As, Ir, and Au, relative to those of non-Antarctic falls. The siderophile enrichments are caused by the oxidation of metallic Fe-Ni to nonmagnetic hydrous Fe-Ni oxides. The concentrations of Fe, Ni, and Co in each sample were used to calculate the amount of oxidized metal, which serves as a quantitative measure of the degree of weathering. The amount of oxidized metal is generally between 1–10 wt% and shows a rough correlation with the qualitative A-B-C-weathering classification for increasing rustiness. No clear correlation was found between weathering and terrestrial age, although meteorites older than 0.2 Ma contain on the average ～50% more oxidized metal. Also, no correlation was found between the degree of weathering and the natural thermoluminescence (TL) level, which is dominated by the thermal history in space rather than by the thermal history in or on the Antarctic ice. The only significant parameter for the degree of weathering seems to be the location of find, with the most weathered specimens being found in a part of the stranding area where melt-water ponds are known to occur. This observation confirms that the occasional presence of liquid water plays an important role in the Antarctic weathering process and explains the poor correlation of the degree of weathering of Antarctic meteorites with terrestrial age and surface exposure age.  相似文献   

18.
For reliable event reconstruction of Imaging Atmospheric Cherenkov Telescopes (IACTs), calibration of the optical throughput efficiency is required. Within current facilities, this is achieved through the use of ring shaped images generated by muons. Here, a complementary approach is explored, achieving cross calibration of elements of IACT arrays through pairwise comparisons between telescopes, focussing on its applicability to the upcoming Cherenkov Telescope Array (CTA). Intercalibration of telescopes of a particular type using eventwise comparisons of shower image amplitudes has previously been demonstrated to recover the relative telescope optical responses. A method utilising the reconstructed energy as an alternative to image amplitude is presented, enabling cross calibration between telescopes of varying types within an IACT array. Monte Carlo studies for two plausible CTA layouts have shown that this calibration procedure recovers the relative telescope response efficiencies at the few per cent level.  相似文献   

19.
Two photoelectric records of the occultation event on 10 March, 1977, obtained by two 102-cm-aperture telescopes, spaced 1500 km apart, are critically analysed and indications of a complex structure of distribution of occulting material surrounding the planet are obtained. The results confirm the existence of a very shallow broad ring system with local condensation lanes of narrow and intermediate widths. A system of numerous thin rings are also present around the planet in the equatorial plane.  相似文献   

20.
ISLA will be an astronomical observatory, operating at the upper limit of our planet Earth atmosphere, offering space like observing conditions in most aspects. ISLA can be maintained easily, modified easily if necessary, always kept at the state of the art and operated for very extended periods without polluting the stratosphere. ISLA is ideally suited to become the first world space observatory as the observing conditions are very much space-like – diffraction limited angular resolution, very low ambient temperature, remote control – however ISLA is easily accessible, telescopes and instruments can be continuously improved and ISLA's costs corresponds only to those of ground-based modern astronomical installations like the ESO-VLT-, KECK- and GEMINI-observatories. The cost of observing and experimenting on ISLA will be orders of magnitudes lower than those of building and operating any space telescope, allowing the astronomers of developing nations to participate in the ISLA observatory within their limited financial possibilities as competent and full partners. ISLA's 4-m and 2-m telescopes will operate diffraction limited from 0.3 μm in the optical, over the infrared, far-infrared to the sub-mm spectral range. ISLA's individual telescopes will permit imaging with 20 milli-arcsec spatial resolution in the optical, 5 times better than the Hubble Space Telescope. ISLA's telescopes can be combined to form an interferometer with a maximum baseline of 250 m with nearly complete coverage of the u,v plane. Interferometric resolution will be of the order of 20 micro-arcsec for the optical. ISLA will thus offer spatial resolution comparable or better than the intercontinental VLBI radio interferometers. ISLA's telescope efficiency will be many orders of magnitude better than comparable ground-based telescopes. The light collecting power of ISLA's interferometric telescopes will be orders of magnitudes greater than the future space interferometers under discussion. ISLA, being an aviation project and not a space project, can be realised in the typical time scale for the development of aviation: about 5 years. ISLA's cost for the whole observatory, including its movable ground station etc. will be of the order of a typical medium size ESA space mission. ISLA's lifetime will be in excess of many decades, as it can easily be maintained, modernised, repaired and improved. ISLA will become the origin of a new astronomical international organisation with worldwide participation. ISLA's telescopes will be of the greatest importance to all astronomical fields, as it will permit to study much fainter, much more distant objects with microscopic spatial resolution in wavelength regions inaccessible from ground. ISLA's many telescopes permit easily simultaneous observations at many wavelengths for rapidly varying objects, from continuously monitoring the surfaces of the planets in our solar system, surfaces of close-by stars, nuclei of galaxies to QSO's. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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