共查询到20条相似文献，搜索用时 93 毫秒
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针对FAST的天文观测要求,对其天文观测软件进行了设计与开发。首先介绍了FAST天文观测的原理,对天文观测软件进行了需求分析。而后提出了馈源天文运动轨迹规划算法,并进行了仿真。针对其轨迹要求给出了控制方法,对天文观测控制软件进行了设计与实现。最后通过现场实地实验,验证了本文所提的算法与软件的可行性。 相似文献
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该文阐述了利用低通滤波器和多相滤波器技术实现VLBI数字基带转换的原理,建立了采用多相滤波器与FFT技术的数字基带转换系统的仿真模型;然后对本模型的算法复杂度进行了分析和比较;最后对该模型的正确性进行了仿真实验验证. 相似文献
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提出了超导磁悬浮望远镜的概念,建立了模型,提出了稳定悬浮方案,并用有限元软件对磁悬浮望远镜的磁场进行了三维静态分析,为南极望远镜水平轴系结构设计提供了新的思路. 相似文献
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2019年见证了太空领域所取得的多项突破。在太阳系内,一个探测器对小行星表面之下的物质进行了采样;天文学家对海王星存档图像的仔细筛查发现了它迄今最小的卫星。此前对冥王星进行了近距离探访的探测器又飞过了另一个更为遥远的天体,为了解行星演化的历史打开了新的窗口。一个新的探测器着陆到了火星上,意在首次了解火星表面之下正在发生些什么。 相似文献
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到了19世纪初,人们在探索星空的道路上已经走出了很远。1801年柏林天文台台长波德出版的《波德星图》（Uranographia）可以被视作此前时代的总结。这份印刷精美的古典星图以极高的精度标出了全天17240颗恒星的位置,包括了所有7等以上的恒星;加入了威廉姆赫歇尔等人发现的2000多个深空天体;还为各个星座划分了明确的边界。接下来的工作就将在这份蓝图上展开…… 相似文献
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Edgar L Andreas 《Icarus》2007,186(1):24-30
The strong hydrogen signal that the Lunar Prospector saw at the Moon's poles suggests that water ice may be present near the surface of the lunar regolith. A robotic mission to obtain in situ samples and to quantify the amount of this valuable resource must be designed carefully to avoid dissipating too much heat in the regolith during coring or drilling and, thus, causing the ice to sublimate before it is processed. Here I use new results for the saturation vapor pressure of water ice to extend previous estimates of its sublimation rate down to a temperature of 40 K, typical of the permanently shaded craters near the lunar poles where the water ice is presumed to be trapped. I find that, for temperatures below 70 K, the sublimation rate of an exposed ice surface is much less than one molecule of water vapor lost per square centimeter of surface per hour. But even if a small ice sample (∼4 ng) were heated to 150 K, it could exist for over two hours without sublimating a significant fraction of its mass. Hence, carefully designed sampling and sample handling should be able to preserve water ice obtained near the lunar poles for an accurate measurement of its in situ concentration. 相似文献
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Tomoyasu Tanigawa Shinsuke Abe Masateru Ishiguro Tadashi Mukai 《Earth, Moon, and Planets》2010,106(1):55-65
We present two scenarios for production of the Quadrantid stream based on two different models for its origin: the extinct
model in which 2003EH1 was an active comet that released the dust particles during past 5000 years, stopping its activity
abruptly in AD 1488; and the split model; in which a catastrophic disruption of an asteroid at AD 1488 released a large number
of dust particles in a single event. We calculate the orbital evolution of test particles released in both cases and derive
the resulting size distribution of surviving meteoroids in the current Quadrantid stream in the form of s
−α
ds, where s denotes the radius of a meteoroid. We find α = 3.1 in the extinct model and 2.0 in the split model. In addition, the radius
of the surviving meteoroids is derived as s >10 μm in the both models. We propose, based on our estimation of the infrared color ratio for the Quadrantid stream derived
from both models, that infrared observations of the Quadrantid stream may determine which origin model is more reasonable. 相似文献
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A. A. Akopian 《Astrophysics》1996,39(4):331-333
A method is suggested for the determination of the distribution function for the mean frequency of supernova explosions, which is similar to the Ambartsumian method for the determination of the distribution function for the mean flare frequency of flare stars. This method has not been applied because of the lack of the required data.Translated fromAstrofizika, Vol. 39, No. 4, pp. 561–566, November, 1996. 相似文献
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Lisa Kaltenegger Malcolm Fridlund Anders Karlsson 《Astrophysics and Space Science》2006,306(3):147-158
The requirements on space missions designed to study Terrestrial exoplanets are discussed. We then investigate whether the
design of such a mission, specifically the Darwin nulling interferometer, can be carried out in a simplified scenario. The
key element here is accepting somewhat higher levels of stellar leakage. We establish detailed requirements resulting from
the scientific rationale for the mission, and calculate detailed parameters for the stellar suppression required to achieve
those requirements. We do this utilizing the Darwin input catalogue. The dominating noise source for most targets in this
sample is essentially constant for all targets, while the leakage diminishes with the square of the distance. This means that
the stellar leakage has an effect on the integration time only for the nearby stars, while for the more distant targets its
influence decreases significantly. We assess the impact of different array configurations and nulling profiles and identify
the stars for which the detection efficiency can be maximized. 相似文献
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The polarimetric Littrow Spectrograph POLIS is designed for vector polarimetry at high angular and spectral resolution. It measures the magnetic field simultaneously in the photosphere and the chromosphere of the sun. Both branches of the polarimetry unit are dual beam systems with a single rotating modulator for both wavelengths and polarizing beam splitters in front of each CCD camera. POLIS has been installed at the VTT on Tenerife and has seen First Light on 17 May 2002. A modified version of POLIS will be developed for the balloon mission Sunrise . That version will have UV capabilities down to 200 nm. 相似文献
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Alain Blanchard 《Astronomy and Astrophysics Review》2010,18(4):595-645
Evidence for an accelerated expansion of the universe as it has been revealed 10 years ago by the Hubble diagram of distant
type Ia supernovae represents one of the major modern revolutions for fundamental physics and cosmology. It is yet unclear
whether the explanation of the fact that gravity becomes repulsive on large scales should be found within general relativity
or within a new theory of gravitation. However, existing evidences for this acceleration all come from astrophysical observations.
Before accepting a drastic revision of fundamental physics, it is interesting to critically examine the present situation
of the astrophysical observations and the possible limitation in their interpretation. In this review, the main various observational
probes are presented as well as the framework to interpret them with special attention to the complex astrophysics and theoretical
hypotheses that may limit actual evidences for the acceleration of the expansion. Even when scrutinized with skeptical eyes,
the evidence for an accelerating universe is robust. Investigation of its very origin appears as the most fascinating challenge
of modern physics. 相似文献
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The problem is considered of determining the shape and dimensions of the passive component in a combined system for offsetting the solar pressure-induced disturbing torque for geostationary spacecraft with asymmetrical solar arrays. The problem statement, numerical solution algorithm, and calculated results are presented. The resulting shape, the study suggests, not only has the required compensation properties but is also the most efficient from the standpoint of manufacture and functional reliability. 相似文献
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S. R. Bourne 《Celestial Mechanics and Dynamical Astronomy》1972,6(2):167-186
This paper describes a method for finding literal expressions for the first order terms in the Moon's co-ordinates. The method is based on the use of rectangular co-ordinates and was originally proposed by Euler. The variation curve and the terms dependent on the first power of the Lunar eccentricity have been obtained. These results are compared with those of Hill and a number of errors in Hill's results have been found. 相似文献