共查询到20条相似文献，搜索用时 15 毫秒
1.
Bruce A. Conway 《Celestial Mechanics and Dynamical Astronomy》1986,39(2):199-211
A root-finding method due to Laguerre (1834–1886) is applied to the solution of the Kepler problem. The speed of convergence of this method is compared with that of Newton's method and several higher-order Newton methods for the problem formulated in both conventional and universal variables and for both elliptic and hyperbolic orbits. In many thousands of trials the Laguerre method never failed to converge to the correct solution, even from exceptionally poor starting approximations. The non-local robustness and speed of convergence of the Laguerre method should make it the preferred method for the solution of Kepler's equation. 相似文献
2.
We propose a criterion for extending the parameter search method (Krishnakumar and Venkatakrishnan, 1997) of estimating the point spread function to solar data. In the parameter search method, the number of pixels with negative intensity values in the restored object is used as an estimator for determining the unknown parameters of the point spread function. As a solar image has a high background, the restored object does not contain negative values, thereby making the method unsuitable for solar data. We propose to use the intrinsic contrast of solar features as a criterion for identifying the unknown parameter. We validate our method through simulations. This method can not be used for image restoration but can be used for monitoring daytime seeing. 相似文献
3.
V. A. Shefer 《Solar System Research》2010,44(2):152-165
We propose a new method for the determination of the preliminary orbit of a small celestial body using three pairs of its
angular coordinates in three moments of time. The method is based on the use of the intermediate orbit we constructed earlier
using three position vectors and the corresponding time moments. This intermediate orbit accounts for the main part of the
perturbations of the motion of the body under study. We compare the results obtained by the classical Lagrange-Gauss method,
Herrick-Gibbs method, generalized Herrick-Gibbs method, and the new method by the examples of the determination of the orbit
of the small planet 1566 Icarus. The comparison showed that the new method is a highly efficient tool for the study of perturbed
motion. It is especially efficient when applied to high-precision observational data covering short arcs of the orbit. 相似文献
4.
Anna P. Kartashova 《Earth, Moon, and Planets》2012,108(3-4):165-173
We present a method for calculations of equatorial coordinates of any point in the single frame of the wide-field TV systems. This method can be applying for the different television systems [wide-field cameras, all-sky cameras, the cameras with the hybrid TV-system (the system with coupled of the Image Intensifier) et al.]. In that system the calculations of distortions are difficult. Therefore, we devised this method which helps decrease errors (due to distortion and the electro-optical system).The method can be used for measuring of equatorial coordinates of meteor tracks under difficult conditions during the observations such as partial cloudiness, small number of stars and large distortions of the coordinate grid in the frame. These restrictions cannot be overcome by other methods. In the case of the small number of stars the present method using of the reference stars received on a series of frames during the observation period. The accuracy of the method has been estimated to be 4′–8′ (for cameras with fov 50°?×?40° at the CCD 720?×?576 pixels) for maximum number of reference points in the frame. The method used 3 reference points for calculation of the equatorial coordinates of the object. One can use this method if the camera was re-oriented as well. We use this method for our wide field of view cameras. 相似文献
5.
Richard L. Branham Jr. 《Celestial Mechanics and Dynamical Astronomy》1988,45(1-3):169-174
The Gauss-Newton method, and calculating a mass that minimizes the variation of residuals are standard techniques for determining planetary masses, but both may fail under certain circums tances. The Gauss-Newton method, in particular, may diverge, and when it converges may converge to a local, rather than global, minimum of the nonlinear regression problem. The simplex method of nonlinear optimization needs no initial estimate for the solution and can be made to converge to a global minimum. It may also be used with non-least squares criteria, such as the L1 criterion, for greater robustness. But the simplex method achieves these advantages at a high computational price. To test the method as a tool for dynamical astronomy, over 12,000 observations of Neptune were used to calculate Pluto's mass. From an initial estimate of 1/1, 812,000 the Gauss-Newton method diverged. The simplex method converged to a more satisfactory 1/22,000,000 with a range of 1/47,000,000 to 1/14,000,000 as indicated by the mean error. Because the simplex method is considerably slower than competing methods, it should be reserved for refractory problems that do not yield facil solutions when tackled by other methods. 相似文献
6.
A method for a time-dependent search for flaring astrophysical sources which can be potentially detected by large neutrino experiments is presented. The method uses a time-clustering algorithm combined with an unbinned likelihood procedure. By including in the likelihood function a signal term which describes the contribution of many small clusters of signal-like events, this method provides an effective way for looking for weak neutrino flares over different time-scales. The method is sensitive to an overall excess of events distributed over several flares which are not individually detectable. For standard cases (one flare) the discovery potential of the method is worse than a standard time-dependent point source analysis with unknown duration of the flare by a factor depending on the signal-to-background level. However, for flares sufficiently shorter than the total observation period, the method is more sensitive than a time-integrated analysis. 相似文献
7.
Tōnu Viik 《Astrophysics and Space Science》1982,86(1):169-178
A generalized principle of invariance is derived for a plane-parallel atmosphere. On the basis of this principle a method for determining the radiation field in a multilayer atmosphere is proposed. This method, the first part of which is the well-known adding method, permits the application to problems involving optically finite as well as semi-infinite atmospheres. The reflecting boundaries may be incorporated, though in that case it is not possible to use the adding method.Some numerical results are given for the standard and Milne problems and for the problem with internal sources. 相似文献
8.
本文针对晚型星红外辐射的一些模型，讨论相应的拟合方法。对有拱星壳层的晚型星的双黑体模型，给出了具体的拟合方法──线性化方法。最后我们就拟合结果及拟合程序编制方面讨论了线性化方法的优缺点。 相似文献
9.
Shinpei Shibata 《Astrophysics and Space Science》1989,161(1):145-158
A numerical method to determine the electromagnetic field of a steadily rotating magnetosphere with an inclined magnetic moment under a given boundary condition on an arbitrary shaped boundary surface is presented. The region may include the light cylinder. The present method, together with a companion method giving particle motion and creation, makes an iterative scheme to obtain a global model of the pulsar magnetosphere. A key problem for explaining the particle acceleration in pulsars is to solve field-aligned electric field in an accelerating region bounded by an ideal-MHD region. The present method is fit to connect a solution for the non-ideal-MHD region with another solution for the ideal-MHD region on a boundary surface whose location should also be solved (i.e., a floating boundary). The integration scheme is based on the boundary element method and it has great advantage as compared with other methods like the finite difference method and the Fourier transformation method. 相似文献
10.
P. Nurmi 《Monthly notices of the Royal Astronomical Society》2001,323(4):911-922
Two long-term simulation methods for cometary orbits, a Monte Carlo method and a direct integration method, are compared with each other. The comparison is done in seven inclination and perihelion distance intervals, and shows differences in dynamical lifetime and capture probabilities for the following main reasons. We use a finite energy step approximation in the Monte Carlo method and the method considers only close approaches with the planets. The differences can be taken into account statistically and it is possible to calculate the correction factors for the capture probability and dynamical lifetime in the Monte Carlo method. Both corrections depend on the inclination and on the value of the minimum energy step. The capture probabilities of the short-period comets originating in the Oort Cloud are calculated by the corrected Monte Carlo method and compared with published results. 相似文献
11.
12.
E. A. Perdios V. S. Kalantonis M. N. Vrahatis 《Celestial Mechanics and Dynamical Astronomy》2002,84(3):231-244
We present an improved method for locating periodic orbits of a dynamical system of arbitrary dimension. The method first employs the characteristic bisection method (CBM) to roughly locate a periodic orbit, followed by the quadratically convergent Newton method to rapidly refine its position. The method is applied to the physically interesting example of the two degrees of freedom photogravitational problem, and shown to surpass the CBM algorithm and Newton's method alone. 相似文献
13.
Mohamed Adel Sharaf 《Astrophysics and Space Science》1978,57(2):469-478
In this paper, we establish a general variational method for Milne's integral equation. Moreover, a recursive computational algorithm for the method is also constructed. To illustrate the precision of the method as well as the computational algorithm, a numerical example forN=20 is given. 相似文献
14.
本文对星表系统差的性质进行了讨论，并分析和评估了目前常用的星表系统差计算方法的优、缺点，从而提出了一个新的星表系统差计算方法．同时也提出了星表系统差计算精度的检验标准．最后对用不同方法计算的系统差进行了分析比较．结果表明，新方法的系统差计算精度好于目前常用的解析方法． 相似文献
15.
I. L. Andronov Jena 《Astronomische Nachrichten》1988,309(2):121-131
The test function for the method proposed by DUMONT, MORGULEFF, RUTILY, and TERZAN (1978) is investigated analytically and numerically for some examples with constant and variable periods. The properties of the test function of the DMRT method are discussed in comparison with that of the leastsquare method. 相似文献
16.
Secondary anisotropies of the cosmic microwave background (CMB) can be detected by using the cross-correlation between the large-scale structure (LSS) and the CMB temperature fluctuations. In such studies, chance correlations of primordial CMB fluctuations with the LSS are the main source of uncertainty. We present a method for reducing this noise by exploiting information contained in the polarization of CMB photons. The method is described in general terms and then applied to our recently proposed optimal method for measuring the integrated Sachs–Wolfe (ISW) effect. We obtain an expected signal-to-noise ratio of up to 8.5. This corresponds to an enhancement of the signal-to-noise ratio by 23 per cent as compared to the standard method for ISW detection, and by 16 per cent w.r.t. our recently proposed method, both for the best-case scenario of having perfect (noiseless) CMB and LSS data. 相似文献
17.
R. R. Cordeiro R. S. Gomes R. Vieira Martins 《Celestial Mechanics and Dynamical Astronomy》1996,65(4):407-419
We present a method to construct a mapping for perturbed systems, in which the perturbations do not need to be conservative. We use a variation of Wisdom and Holman's method, where the dissipative term is placed together with the other perturbative terms. The method is applied for two dissipative systems: one including gas drag and the other including Poynting-Robertson drag. We compare the results with those obtained by Malhotra's mapping. Because the dissipative part in our method is treated as a regular perturbative term, there is no need for analytical developments of the nonconservative terms. This is a great advantage in itself and this also allows for a fast performance of the integrator. 相似文献
18.
A first-order, semi-analytical method for the long-term motion of resonant satellites is introduced. The method provides long-term solutions, valid for nearly all eccentricities and inclinations, and for all commensurability ratios. The method allows the inclusion of all zonal and tesseral harmonics of a nonspherical planet.We present here an application of the method to a synchronous satellite includingonly theJ
2 andJ
22 harmonics. Global, long-term solutions for this problem are given for arbitrary values of eccentricity, argument of perigee and inclination. 相似文献
19.
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
20.
George H. Born 《Celestial Mechanics and Dynamical Astronomy》1970,2(1):103-113
In this paper, a combination analytical-numerical integration method for solving the differential equations of a modified set of Lagrange's planetary equations is described. The integration method is an Encke-type method because it involves integrating the deviations between the actual trajectory and a reference trajectory. The reference trajectory is obtained from an analytical solution containing the dominant secular and periodic effects of the gravitational field of the primary body. A set of nonsingular elements is used so that the method will be valid for all circular and elliptical motions. It is shown that the method is an accurate and efficient means of satellite ephemeris generation.This paper was presented at the AIAA/AAS Meeting, Princeton University, August 1969. 相似文献