Artículos de revistas: "Ephemerides"

1

Standish, E. M. "The Dynamical Reference Frame". Symposium - International Astronomical Union 166 (1995): 109–16. http://dx.doi.org/10.1017/s0074180900227939.

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Planetary and lunar ephemerides continue to improve in accuracy as they continue to be adjusted to newer and more accurate observational data. An additional improvement will be that of the orientation of the ephemerides; in the future, the ephemerides produced at JPL will be based upon the reference frame of the radio source catalogues. Recent planetary observations have been made directly with respect to the radio reference frame, and these observations have shown a satisfying degree of absolute accuracy and internal consistency; they enable the automatic orientation of the ephemerides onto the radio reference system during the ephemeris adjustment process.

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2

Xi, X. J. y A. Vienne. "Analytical representation for ephemeride with short time spans". Astronomy & Astrophysics 635 (marzo de 2020): A91. http://dx.doi.org/10.1051/0004-6361/201937148.

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Context. The ephemerides of natural satellites resulting from numerical integration have a very good precision on the fitting to recent observations, in a limited interval. Meanwhile, synthetic ephemerides like the Théorie Analytique des Satellites de Saturne (TASS) by Vienne and Duriez describe in detail the dynamical system by a representation based on the combinations of the proper frequencies. Some theoretical studies need to have both advantages. For example, to study the rotation of Titan, one needs to know the representation of its longitude. Aims. We aim to use these two types of ephemerides in order to rebuild a long-lasting and high-precision ephemeris with proper frequencies based on the numerical integration ephemeris. The aim is to describe the numerical ephemerides with formulas similar to analytical ones. Methods. We used the representation of the orbital elements from the TASS ephemeris analysed over 10 000 years as a reference template. We obtained the proper frequencies with both numerical and the TASS ephemeris over 1000 years only. A least-square procedure allowed us to get the analytical representation of an orbital element in this limited interval. Results. We acquire the representation of the mean longitude of Titan from JPL ephemeris over 1000 years. For almost all components, the corresponding amplitudes and phases are similar to the relative terms from TASS. The biggest difference between our representation and the mean longitude of Titan of JPL is less than 100 km over 1000 years, and the standard deviation is about 26 km.

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3

Fukushima, Toshio, George H. Kaplan, George A. Krasinsky, Jean Eudes Arlot, John A. Bangert, Catherine Y. Hohenkerk, George A. Krasinsky et al. "COMMISSION 4: EPHEMERIDES". Proceedings of the International Astronomical Union 4, T27A (diciembre de 2008): 5–11. http://dx.doi.org/10.1017/s1743921308025234.

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JPL planetary ephemeris development has been very active assimilating measurements from current planetary missions and supporting future missions. The NASA Mars Science Laboratory (MSL) mission with launch in 2009 requires knowledge of the Earth and Mars ephemerides with 30m accuracy. By comparison, the accuracy of the Mars ephemeris in the widely used DE405 ephemeris was about 3 km. Meeting the MSL needs requires an ongoing program of range and very-long baseline interferometry measurements of Mars orbiting spacecraft. The JPL ephemeris DE421 was released three months before the landing of the Phoenix mission on Mars, and has met the 300m requirement. Continued measurements are planned to support the MSL landing.

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4

Lee, H. S., W. A. Wan Aris, T. A. Musa y A. Ahmad. "ASSESSING EFFICIENCY OF GPS EPHEMERIDES IN DIFFERENT REGION USING PRECISE POINT POSITIONING". International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVIII-4/W6-2022 (7 de febrero de 2023): 195–99. http://dx.doi.org/10.5194/isprs-archives-xlviii-4-w6-2022-195-2023.

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Abstract. Precise Point Positioning (PPP) is a technique that process Global Positioning System (GPS) observation that can achieve sub-decimetre accuracy. Precise ephemerides that contain satellite clock and position plays a vital role in minimising orbital and clock error in PPP. This study hypothesize that the efficiency of ephemerides varies across region, influenced by the density of stations involved in generating the ephemerides. GPS observations from stations in five different regions were processed using PPP technique by using RTKLIB. Four types of ephemerides were used namely broadcast, ultra-rapid, rapid, and final ephemerides during the processing of each station. Root-mean-squared error (RMSE) of 3D error of the PPP solution for the stations in each region is quantified. Among the five regions selected, Europe has the lowest RMSE of 155.67 cm, 27.93 cm, 27.38 cm and 27.06 cm for broadcast, ultra-rapid, rapid, and final ephemeris respectively. This high accuracy can be attributed to the density of International GNSS Service (IGS) stations in Europe that are available for the generation of ephemerides. Position Dilution of Precision (PDOP) was also found to contribute to the accuracy of PPP solution in a region, whereby a low PDOP often promises higher positioning accuracy. More regional stations are suggested to be involved in the generation of ephemerides to improve the efficiency of ephemerides in that region.

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5

Deng, Yongtao y Shuanggen Jin. "Effect of Ephemeris on Pulsar Timing and Navigation Accuracy Based on X-ray Pulsar Navigation-I Data". Universe 8, n.º 7 (27 de junio de 2022): 360. http://dx.doi.org/10.3390/universe8070360.

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Solar system ephemeris is very important for pulsar timing and navigation. In order to explore the effect of different precision ephemerides on X-Ray pulsar timing and navigation, the differences between timing and navigation results with four JPL Development Ephemerides based on the data of x-ray pulsar navigation-I (XPNAV-I) were compared and analyzed in this paper. For pulsar timing, the ephemeris has a systematic effect on time scale conversion (nanosecond difference), light-travel delay (millisecond difference) and timing residuals (microsecond difference), and the pulse profile phase can reflect the systematic deviation caused by different ephemerides in the timing calculation. The timing results show that it is necessary to compile the pulsar timing model based on the newer ephemeris. For navigation, based on the significant enhancement of pulse profile with orbit-dynamic (SEPO), the absolute error between simulation orbit and actual orbit is less than 2 km for each ephemeris, and the differences between simulation orbits are less than 1 km. The orbit position accuracy calculated by the ephemeris used in pulsar timing parameter calculation is the highest (DE200 in this paper), which explains the necessity of using a unified ephemeris in the calculation of timing and navigation with satisfying its internal self-consistency.

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6

Standish, E. Myles. "Numerical planetary and lunar ephemerides: present status, precision and accuracies". Symposium - International Astronomical Union 114 (1986): 71–83. http://dx.doi.org/10.1017/s0074180900148016.

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The Ephemeris Development Program has been in existence for nearly 20 years at JPL, providing high precision present-day knowledge of the positions of the moon and major planets. The resultant ephemerides are used extensively in the navigation of spacecraft and in the reduction of astrometric observations. They also provide a key element in the testing of various theories of gravitation and a means for the determination of various relevant astronomical constants. The ephemerides and the process of creating them are both shown to be viable tools for the measurement of various gravitational effects which govern the motions of the objects in the solar system.This paper gives an outline of the least-squares adjustment of the ephemerides to the observations, the present physical (dynamical) model, the present observations to which the ephemerides are fit, the expected accuracies of various ephemeris elements, recent and future observations and features of the solar system which are poorly determined (and thereby place limits upon the accuracies). Recent comparisons with similar work at the Center for Astrophysics (formerly at MIT) are serving as valuable independent checks on formulations and procedures used at each institution; they also lend insight toward what are the realistic accuracies being attained. The export procedure, by which an outside user may obtain and use the JPL ephemerides, is described.

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7

Morando, B., P. K. Seldelmann, V. K. Abalakin, S. Aokl, J. Chapront, R. L. Duncombe, T. Lederle, J. H. Lieske, B. D. Yallop y A. Yamazaki. "4. Ephemerides (Ephemerides)". Transactions of the International Astronomical Union 20, n.º 1 (1988): 1–6. http://dx.doi.org/10.1017/s0251107x00006854.

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This report covers the period from 1 July 1984 to 30 June 1987. The ephemerides that have been published during this period have made use of the new system of astronomical constants adopted at the XVIth General Assembly of the lAU in Grenoble. Yet some difficulties have arisen because of the lack of catalogues or maps of the heavens established for the epoch J2000.0. This is awkward for observers of comets and minor planets and, for that reason, Commission 20 decided, at the New Delhi meeting of lAU that there would be a gradual introduction of the J2000.0 system as far as those bodies are concerned.

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8

Emelyanov, N. V., M. I. Varfolomeev y V. Lainey. "New ephemerides of outer planetary satellites". Monthly Notices of the Royal Astronomical Society 512, n.º 2 (24 de marzo de 2022): 2044–50. http://dx.doi.org/10.1093/mnras/stac586.

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ABSTRACT Ephemerides of planetary satellites require regular updates to take into account new observations of the satellites. Such revision has been all the more necessary in the case of outer planetary satellites, since a number of new moons have been discovered recently. Thus, we present updated versions of the ephemerides of the outer planetary satellites. The problem and the methodology for estimating ephemeris accuracy are discussed. Comparison with the Jet Propulsion Laboratory (JPL) ephemerides proves that the accuracy depends largely on the distribution of the observations. We give examples where, for a few satellites, the O−C residuals increase sharply at time intervals lying significantly beyond the time interval of observations used to generate the ephemerides. This fact alone indicates that there is an urgent need for new observations. Besides the ephemerides of moons, which can be accessed online via the MULTI-SAT server, we provide orbital parameters for the recently discovered faint satellites of Jupiter and Saturn. The problems discussed in this work are important for planning space observations of the outer satellites by future space missions like the European Space Agency (ESA) JUpiter ICy moons Explorer (JUICE) and National Aeronautics and Space Administration (NASA) Europa Clipper missions.

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9

Krasinsky, George, Toshio Fukushima, J. Chapront, E. M. Standish, C. Hohenkerk, G. Kaplan, P. K. Seidelmann, J. Bangert, S. Urban y J. Vondrak. "Commission 4: Ephemerides". Proceedings of the International Astronomical Union 1, T26A (diciembre de 2005): 3–6. http://dx.doi.org/10.1017/s1743921306004285.

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JPL continues to be active in creating ephemerides in support of spacecraft navigation as well as various other functions. Many of the products are available on web sites: (a) “Horizons”, the interactive web site, updated on an hourly basis, is located at http://ssd.jpl.nasa.gov. As of August, 2005, it contains orbital elements and ephemerides for the sun and 9 planets, 150 natural satellites (including the Moon), 291, 655 asteroids, 1631 comets, and 34 Spacecraft. Horizons uses the full precision of the JPL DE405.(b)JPL's Planetary and Lunar Ephemerides in “export” format are available via FTP from the Internet: ftp://ssd.jpl.nasa.gov/pub/eph/export/ or on a CD-ROM: http://www.willbell.com/software/jpl.htm We advise to read the attached README.(c)The observational data used in fitting the planetary ephemerides is available at the following web site, updated periodically: http://ssd.jpl.nasa.gov/plan-eph-data/(d)SPICE Toolkit is a subroutine package for experienced programmers who write their own main driving programs for astrometrical computations. SPICE is available at http://naif.jpl.nasa.gov/. It contains a large library of subroutines useful in reading SPICE format ephemeris files (SPK) and in computing many solar system observation geometry parameters associated with the various JPL solar system missions. Available in Fortran, C, and IDL for most popular computing platforms.

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10

Mariani, V., O. Minazzoli, A. Fienga, J. Laskar y M. Gastineau. "Bayesian test of Brans–Dicke theories with planetary ephemerides: Investigating the strong equivalence principle". Astronomy & Astrophysics 682 (febrero de 2024): A175. http://dx.doi.org/10.1051/0004-6361/202348082.

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Aims. We are testing the Brans–Dicke class of scalar tensor theories with planetary ephemerides. Methods. In this work, we apply our recently proposed Bayesian methodology to the Brans–Dicke case, with an emphasis on the issue of the strong equivalence principle (SEP). Results. We use an MCMC approach coupled to full, consistent planetary ephemeris construction (from point-mass body integration to observational fit) and compare the posterior distributions obtained with and without the introduction of potential violations of the SEP. Conclusions. We observe a shift in the confidence levels of the posteriors obtained. We interpret this shift as marginal evidence that the effect of violation of the SEP can no longer be assumed to be negligible in planetary ephemerides with the current data. We also notably report that the constraint on the Brans–Dicke parameter with planetary ephemerides is getting closer to the figure reported from the Cassini spacecraft alone, and also to the constraints from pulsars. We anticipate that data from future spacecraft missions, such as BepiColombo, will significantly enhance the constraints based on planetary ephemerides.

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11

Fukushima, Toshio. "Commission 4: Ephemerides (Ephemerides)". Transactions of the International Astronomical Union 25, n.º 2 (2007): 65–66. http://dx.doi.org/10.1017/s0251107x00026481.

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12

Chapront, J., G. A. Krasinsky, V. K. Abalakin, J. E. Arlot, T. Fukushima, M. F. He, C. Y. Hohenkerk et al. "Commission 4: Ephemerides: (Ephemerides)". Transactions of the International Astronomical Union 25, n.º 1 (2002): 11–14. http://dx.doi.org/10.1017/s0251107x00001231.

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13

Battley, Matthew P., Michelle Kunimoto, David J. Armstrong y Don Pollacco. "Revisiting theKeplerfield withTESS: Improved ephemerides usingTESS2 min data". Monthly Notices of the Royal Astronomical Society 503, n.º 3 (10 de marzo de 2021): 4092–104. http://dx.doi.org/10.1093/mnras/stab701.

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ABSTRACTUp to date planet ephemerides are becoming increasingly important as exoplanet science moves from detecting exoplanets to characterizing their architectures and atmospheres in depth. In this work, ephemerides are updated for 22 Kepler planets and 4 Kepler planet candidates, constituting all Kepler planets and candidates with sufficient signal to noise in the TESS 2 min data set. A purely photometric method is utilized here to allow ephemeris updates for planets even when they do not posses significant radial velocity data. The obtained ephemerides are of very high precision and at least seven years ‘fresher’ than archival ephemerides. In particular, significantly reduced period uncertainties for Kepler-411d, Kepler-538b, and the candidates K00075.01/K00076.01 are reported. O–C diagrams were generated for all objects, with the most interesting ones discussed here. Updated TTV fits of five known multiplanet systems with significant TTVs were also attempted (Kepler-18, Kepler-25, Kepler-51, Kepler-89, and Kepler-396), however these suffered from the comparative scarcity and dimness of these systems in TESS. Despite these difficulties, TESS has once again shown itself to be an incredibly powerful follow-up instrument as well as a planet-finder in its own right. Extension of the methods used in this paper to the 30 min-cadence TESS data and TESS extended mission has the potential to yield updated ephemerides of hundreds more systems in the future.

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14

Standish, E. M. y X. X. Newhall. "New accuracy levels for solar system ephemerides". Symposium - International Astronomical Union 172 (1996): 29–36. http://dx.doi.org/10.1017/s0074180900127081.

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DE403/LE403 is the latest JPL Planetary and Lunar Ephemeris. It represents a number of changes and improvements to previous JPL ephemerides: the reference frame is now that of the IERS, newer and more accurate observations are used in the adjustment process, some of the data reduction techniques have been refined, and improved dynamical modeling has been incorporated into the equations of motion. As a result, the internal accuracy of the inner four planets has been improved. Further, various measurements accurately tie Jupiter onto the IERS Reference Frame. In the future, use of CCD measurements and the Hipparcos Catalogue should improve the ephemerides of the outermost four planets.DE403/LE403 has been integrated over 6000 years, from 3000 BC to 3000 AD. A more condensed representation has been made from this, named DE404/LE404. It replaces DE102 as the new JPL “Long Ephemeris”.

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15

Pang, Kevin D. y Kevin K. Yau. "The need for more accurate 4000-year ephemerides, based on lunar and spacecraft ranging, ancient eclipse and planetary data". Symposium - International Astronomical Union 172 (1996): 113–16. http://dx.doi.org/10.1017/s0074180900127202.

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Long planetary and lunar ephemerides like the JPL DE102 and LE51 (Newhall et al., 1983) and the Bureau des Longitudes VSOP (Bretagnon, 1982) and ELP (Chapront-Touze and Chapront, 1983) have enabled more positive ancient eclipse, planetary and cometary identifications, which have in turn refined ephemerides, e.g., the reconstruction of the orbit of comets Halley and Swift-Tuttle (Yeomans and Kiang, 1981; and Yau et al., 1994). The data used to initialize DE102 are pre-1977. Much more observational data have been collected since. The lunar ephemeris has also been improved. The secular lunar acceleration, , from laser ranging, is −25.9±0.5″/cen2 (Williams et al., 1992). We can now uniquely solve for ΔT, the clock error, from ancient eclipse records. The lack of ΔT values before 700 B.C. has left the early timescale of the ephemerides unconstrained (Morrison, 1992). Our solution of this problem is outlined here.

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16

Qiao, Jing, Wu Chen, Shengyue Ji y Duojie Weng. "Accurate and Rapid Broadcast Ephemerides for Beidou-Maneuvered Satellites". Remote Sensing 11, n.º 7 (2 de abril de 2019): 787. http://dx.doi.org/10.3390/rs11070787.

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The geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites of the Beidou navigation satellite system are maneuvered frequently. The broadcast ephemeris can be interrupted for several hours after the maneuver. The orbit-only signal-in-space ranging errors (SISREs) of broadcast ephemerides available after the interruption are over two times larger than the errors during normal periods. To shorten the interruption period and improve the ephemeris accuracy, we propose a two-step orbit recovery strategy based on a piecewise linear thrust model. The turning points of the thrust model are firstly determined by comparison of the kinematic orbit with an integrated orbit free from maneuver; afterward, precise orbit determination (POD) is conducted for the maneuvered satellite by estimating satellite orbital and thrust parameters simultaneously. The observations from the IGS Multi-Global Navigation Satellite System (GNSS) Experiment (MGEX) network and ultra-rapid products of the German Research Center for Geosciences (GFZ) are used for orbit determination of maneuvered satellites from Sep to Nov 2017. The results show that for the rapidly recovered ephemerides, the average orbit-only SISREs are 1.15 and 1.0 m 1 h after maneuvering for GEO and IGSO respectively, which is comparable to the accuracy of Beidou broadcast ephemerides in normal cases.

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17

Eroshkin, G. I., N. I. Glebova, M. A. Fursenko y A. A. Trubitsina. "Some Aspects of Constructing Long Ephemerides of the Sun, Major Planets and the Moon: Ephemeris AE95". International Astronomical Union Colloquium 165 (1997): 245–50. http://dx.doi.org/10.1017/s0252921100046625.

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The construction of long-term numerical ephemerides of the Sun, major planets and the Moon is based essentially on the high-precision numerical solution of the problem of the motion of these bodies and polynomial representation of the data. The basis of each ephemeris is a mathematical model describing all the main features of the motions of the Sun, major planets, and Moon. Such mathematical model was first formulated for the ephemerides DE/LE and was widely applied with some variations for several national ephemeris construction. The model of the AE95 ephemeris is based on the DE200/LE200 ephemeris mathematical model. Being an ephemeris of a specific character, the AE95 ephemeris is a basis for a special edition “Supplement to the Astronomical Yearbook for 1996–2000”, issued by the Institute of the Theoretical Astronomy (ITA) (Glebova et al., 1995). This ephemeris covering the years 1960–2010 is not a long ephemeris in itself but the main principles of its construction allow one to elaborate the long-term ephemeris on an IBM PC-compatible computer. A high-precision long-term numerical integration of the motion of major bodies of the Solar System demands a choice of convenient variables and a high-precision method of the numerical integration, taking into consideration the specific features of both the problem to be solved and the computer to be utilized.

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18

Tang, K., Y. Z. Song, K. X. Shen, R. C. Qiao, Z. H. Tang, Y. Yu, H. Y. Zhang y D. Yan. "The orbit of Triton with new precise observations and the INPOP19a ephemeris". Astronomy & Astrophysics 641 (septiembre de 2020): A108. http://dx.doi.org/10.1051/0004-6361/202038556.

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Aims. The Gaia catalogue brings new opportunities and challenges to high-precision astronomy and astrometry. The precision of data reduction is therefore improved by a large number of reference stars with high-precision positions and proper motions. Numerous precise positions for Triton are obtained from the latest observations using the Gaia catalogue. Furthermore, the new INPOP19a planetary ephemeris, which also fits the observations from the Gaia Data Release 2, has recently become available. In this paper, a new orbit of Triton is calculated using the latest precise charge-coupled device (CCD) observations and the INPOP19a ephemeris. Methods. Triton’s orbital solution is calculated using a numerical integrator, while the orientation of Neptune’s pole in particular is obtained by integrating the simplified Euler’s equations of motion. We determine the orbit of Triton over 170 yr based on 11 040 Earth-based observations made between 1847 and 2016 and on Voyager 2 data. The positions of the Sun and planets are provided by the INPOP19a ephemeris. We compare our results to those from other previous works to check the influences on Triton’s orbit from different planetary ephemerides. Results. A new orbit of Triton is provided here. The root-mean-square of the residuals for the Earth-based CCD absolute observations are 0.102″ in right ascension and 0.142″ in declination. Although most different planetary ephemerides have large differences in Neptune’s position, the orbits of Triton using different planetary ephemerides are still close, under similar dynamical models. The Voyager 2 data add a constraint on Triton’s orbit here.

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19

Yeomans, Donald K. "Comet and Asteroid Ephemerides for Spacecraft Encounters". International Astronomical Union Colloquium 165 (1997): 1–12. http://dx.doi.org/10.1017/s0252921100046315.

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AbstractTo a significant degree, the success of spacecraft missions to comets and asteroids depends upon the accuracy of the target body ephemerides. In turn, accurate ephemerides depend upon the quality of the astrometric data set used in determining the object’s orbit and the accuracy with which the target body’s motion can be modelled. Using error analyses studies of the target bodies for the NEAR, Muses-C, Clementine 2, Stardust, and Rosetta missions, conclusions are drawn as to how to minimize target body position uncertainties at the times of encounter. In general, these uncertainties will be minimized when the object has a good number of optical observations spread over several orbital periods. If a target body lacks a lengthy data interval, its ephemeris uncertainties can be dramatically reduced with the use of radar Doppler and delay data taken when the body is relatively close to the Earth. The combination of radar and optical angle data taken at close Earth distances just before a spacecraft encounter can result in surprisingly small target body ephemeris uncertainties.

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20

Standish, E. M. "Celestial Reference Frames: Definitions and Accuracies". Symposium - International Astronomical Union 129 (1988): 309–15. http://dx.doi.org/10.1017/s0074180900134813.

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The determination of a specific catalogue or ephemeris reference frame is a highly over-determined problem, depending on the particular selection of which coordinates, which objects and at what time(s) the determination is made. The consistency which various determinations exhibit is dependent upon the accuracy of the catalogue or ephemeris itself. This paper discusses the accuracies of the three most prominent celestial reference frames: stellar catalogues, the lunar and planetary ephemerides and the radio source catalogues.The FK4 stellar catalogue contains known systematic errors amounting to a few tenths of an arcsecond; the FK5 will yield nearly an order of magnitude improvement; HIPPARCOS and Space Telescope expectby the mid 1990's optical interferometry should approachwithin a couple of years, tens of micro(!)arcseconds after a couple of decades. Present-day lunar and planetary ephemerides have accuracies at the level offor the moon and inner four planets;for the outer planets. Further observational data will permit continued improvement. Radio source catalogues now show internal consistency of

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21

Capistrano, Abraão J. S., Joice A. M. Penagos y Manuel S. Alárcon. "Heuristic Approach on Anomalous Apsidal Precession of Planets". International Journal of Modern Physics: Conference Series 45 (enero de 2017): 1760074. http://dx.doi.org/10.1142/s2010194517600746.

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In this paper we study the anomalous movement of planet precession as compared with different observational data from Ephemerides of the Planets and the Moon (EPM2008 and EPM2011) and the Planetary and Lunar Ephemeris (INPOP10a). Using a heuristic methodology we obtain a very close results to observations.

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22

Jones, Ellen. "Ephemerides". Moreana 22 (Number 87-8, n.º 3-4 (noviembre de 1985): 97–98. http://dx.doi.org/10.3366/more.1985.22.3-4.30.

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23

Sander-Regier, Renate. "Ephemerides". Moreana 23 (Number 89), n.º 1 (febrero de 1986): 99–102. http://dx.doi.org/10.3366/more.1986.23.1.25.

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24

Sander-Regier, Renate. "Ephemerides". Moreana 23 (Number 91-9, n.º 3-4 (diciembre de 1986): 88–92. http://dx.doi.org/10.3366/more.1986.23.3-4.24.

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25

Marc’hadour, Germain. "Ephemerides". Moreana 23 (Number 91-9, n.º 3-4 (diciembre de 1986): 93–96. http://dx.doi.org/10.3366/more.1986.23.3-4.25.

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26

Marc’hadour, Germain. "Ephemerides". Moreana 23 (Number 91-9, n.º 3-4 (diciembre de 1986): 206–11. http://dx.doi.org/10.3366/more.1986.23.3-4.56.

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27

Marc’hadour, Germain. "Ephemerides". Moreana 25 (Number 98-9, n.º 2-3 (diciembre de 1988): 237–38. http://dx.doi.org/10.3366/more.1988.25.2-3.56.

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28

Standish, E. M. "Fundamental Arguments of the Current Nutation Theory: Dynamical Reference Frame". Highlights of Astronomy 11, n.º 1 (1998): 168. http://dx.doi.org/10.1017/s1539299600020347.

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The latest JPL planetary and lunar ephemerides, DE405, are now referenced to the ICRF with an accuracy of about 1 mas. This has been accomplished mainly by fitting the ephemerides to 18 VLBI observations of the Magellan Spacecraft in orbit around Venus, 1990-1994, and to 2 VLBI observations of the Phobos Spacecraft in its approach to Mars, 1989. The orientation of DE405 is discussed in more detail elsewhere in this volume (Standish, 1997). Since all of the parameters of the inner solar system are now determined to 1 mas or better, one should be able to extract numerically the fundamental arguments of the nutation theories to the level of 1 mas.There are two ways of extracting the ecliptic, for example, from a numerical ephemeris: 1) one computes the node and obliquity of the instantaneous ecliptic at multiple points in time and then fits these with analytic functions, or 2) one fits an analytical planetary theory to the ephemerides and then computes the node and obliquity from the theory’s parameters. This paper relates a short example using method #1 and concludes that method #2 is probably more preferable.

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29

Wang, Wenqin, Zixin Zhang, Zhangliang Chen, Yonghao Wang, Cong Yu y Bo Ma. "Long-term Variations in the Orbital Period of Hot Jupiters from Transit-timing Analysis Using TESS Survey Data". Astrophysical Journal Supplement Series 270, n.º 1 (1 de enero de 2024): 14. http://dx.doi.org/10.3847/1538-4365/ad0847.

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Abstract Many hot Jupiters may experience orbital decays, which are manifested as long-term transit-timing variations. We have analyzed 7068 transits from the Transiting Exoplanet Survey Satellite (TESS) for a sample of 326 hot Jupiters. These new mid-transit-time data allow us to update ephemerides for these systems. By combining the new TESS transit-timing data with archival data, we searched for possible long-term variations in the orbital period in these hot Jupiters using a linear and a quadratic ephemeris model. We identified 26 candidates that exhibit possible long-term variations of the orbital period, including 18 candidates with decreasing orbital periods and eight candidates with increasing orbital periods. Among them, 12 candidates failed our leave-one-out cross validation test and thus should be considered to be marginal candidates. In addition to tidal interaction, alternative mechanisms such as apsidal precession, the Rømer effect, and the Applegate effect could also contribute to the variations during the observed period. The ephemerides derived in this work are useful for scheduling follow-up observations for these hot Jupiters in the future. The Python code (PdotQuest, https://github.com/AeoN400/PdotQuest) used to generate the ephemerides is made available online.

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30

Robustelli, Umberto y Giovanni Pugliano. "Galileo Single Point Positioning Assessment Including FOC Satellites in Eccentric Orbits". Remote Sensing 11, n.º 13 (30 de junio de 2019): 1555. http://dx.doi.org/10.3390/rs11131555.

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On August 2016, the Milena (E14) and Doresa (E18) satellites started to broadcast ephemeris in navigation message for testing purposes. As the Galileo constellation is not yet complete. It is very important to have two more satellites available since the position accuracy increases as the number of visible satellites increases. In this article, we examine how the inclusion of the Milena (E14) and Doresa (E18) satellites impacts the position accuracy. The analysis was carried out on 20 days of 1-Hz observations collected by a receiver placed in YEL2IGS (International GNSS service) station. Two different scenarios are considered: the first excludes the measurements coming from the analyzed satellites, while the second one includes them. The analysis was conducted by using a suitable software tool developed in the MATLAB® environment able to compute satellites position from both the broadcast and precise ephemerides, to assess DOP (Dilution Of Precision) parameters and to compute single-point positioning for all Galileo frequencies. The analyses are conducted by using both broadcast and precise ephemeris. The inclusion of the two satellites improves the system availability, varying it from 94.1–97.94%, the DOP parameters, and the percentages of achieved positioning solutions by about 5% regardless of the frequency used. Nevertheless, in the positioning domain, when the broadcast ephemerides are used, the inclusion of the satellites worsens both the horizontal and vertical accuracy of the solution. The deterioration of the horizontal accuracy goes from 0.17 m with E5a frequency measurements to 0.74 m with E1 measurements. The reduction of vertical accuracy goes from 0.68 m for E5a to 1.2 m for E1 measurements. However, if precise ephemerides are used, both the horizontal and the vertical accuracy remain stable, actually for the E5b frequency, the DRMS (Distance Root Mean Squared) improves by almost 0.5 m. The results achieved show that the real drawback to overcome is related to the quality of broadcast ephemeris as, when precise ephemeris are used, the number of solutions achieved is increased by about 5% with an accuracy similar to that obtained when the satellites are excluded.

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31

Seidelmann, P. K. "Evolution of Ephemerides Representation and Diffusion". Symposium - International Astronomical Union 172 (1996): 331–38. http://dx.doi.org/10.1017/s0074180900127627.

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There has been, and continues to be, a close interaction between celestial mechanics used for the generation of ephemerides, mathematical techniques, and computer technology. As the computer capabilities of the ephemerides offices and the users of ephemerides have improved, the methods of determining and the accuracies of ephemerides have changed and the medium and representation of the ephemerides provided to the user have evolved.Ephemerides have been provided in the form of theories, tables, tabulations, polynomials, graphics, and subroutines by means of the printed page, punched cards, magnetic tape, floppy disks, CD/ROMs, and electronic mail. As mathematical techniques and computer technology continue to develop and the requirements for ephemerides evolve, the methods of representing and diffusing ephemerides will continue to improve.

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32

Standish, E. M., X. X. Newhall, J. G. Williams y J. O. Dickey. "The reference frame of the ephemerides". Symposium - International Astronomical Union 128 (1988): 49–53. http://dx.doi.org/10.1017/s0074180900119254.

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Complete ephemerides of the moon and the four inner planets could be created solely from ranging data alone. Such ephemerides would then be independent from any outside astronomical reference system, and, therefore, would define their own unique reference frame. In fact, this is nearly the case with present-day ephemerides; the accuracy of the ranging data tends to dominate most of the least squares adjustment.This paper outlines the process of creating the lunar and planetary ephemerides along with the orientation of the ephemerides onto the dynamical equinox. The resulting accuracies of these processes are given and a number of uses for the ephemerides are highlighted.

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33

Abdel Aziz, Khaled Mahmoud y Loutfia Elsonbaty. "EFFECT OF USING DIFFERENT SATELLITE EPHEMERIDES ON GPS PPP AND POST PROCESSING TECHNIQUES". Geodesy and cartography 47, n.º 3 (13 de octubre de 2021): 104–10. http://dx.doi.org/10.3846/gac.2021.13762.

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The orbital error is one of the errors in GPS which affect the accuracy of GPS positioning. In this research GPS broadcast, ultra-rapid, rapid and precise satellite ephemerides are used for processing different baseline lengths among some CORS stations by using the Trimble Business Center software (TBC) and different satellite ephemerides (NRCan ultra-rapid, NRCan rapid and IGS final) are tested in CSRS-PPP online application at the same CORS stations. In this research, when using TBC software for processing the different baseline lengths by using the different satellite ephemerides and compared the coordinates of CORS stations which obtained from the different satellite ephemerides with each other. The results showed that the best satellite ephemerides closest to rapid and final satellite ephemerides are the ultra-rapid (00 UTC) and ultra-rapid (06 UTC). When processing the same CORS stations which used at TBC on CSRSPPP online application by using the different satellite ephemerides it is found also that the NRCan ultra-rapid closest to final satellite ephemerides.

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34

Coma, J. C., M. Lara y T. J. López Moratalla. "Fast evaluation of ephemerides by polynomial approximation in the Chebyshev norm". Symposium - International Astronomical Union 172 (1996): 345–46. http://dx.doi.org/10.1017/s0074180900127640.

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Normally the planetary and satellite ephemerides are provided in tabular form, where the user interpolates between points in order to obtain the ephemerides. There are other methods of providing ephemerides by means of polynomial representations. The user is supplied with the coefficients of a set of polynomials which allow him a fast ephemerides evaluation.

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35

Di Ruscio, A., A. Fienga, D. Durante, L. Iess, J. Laskar y M. Gastineau. "Analysis of Cassini radio tracking data for the construction of INPOP19a: A new estimate of the Kuiper belt mass". Astronomy & Astrophysics 640 (28 de julio de 2020): A7. http://dx.doi.org/10.1051/0004-6361/202037920.

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Context. Recent discoveries of new trans-Neptunian objects have greatly increased the attention by the scientific community to this relatively unknown region of the solar system. The current level of precision achieved in the description of planet orbits has transformed modern ephemerides in the most updated tools for studying the gravitational interactions between solar system bodies. In this context, the orbit of Saturn plays a primary role, especially thanks to Cassini tracking data collected during its 13-year mission around the ringed planet. Planetary ephemerides are currently mainly built using radio data, in particular with normal points derived from range and Doppler observables exchanged between ground stations and interplanetary probes. Aims. We present an analysis of Cassini navigation data aimed at producing new normal points based on the most updated knowledge of the Saturnian system developed throughout the whole mission. We provide additional points from radio science dedicated passes of Grand Finale orbits and Titan flybys. An updated version of the INPOP planetary ephemerides based upon these normal points is presented, along with a new estimate of the mass of trans-Neptunian object rings located in the 2:1 and 3:2 mean motion resonances with Neptune. Methods. We describe in detail the orbit determination process performed to construct the normal points and their associated uncertainties and how we process those points to produce a new planetary ephemeris. Results. From the analysis, we obtained 623 new normal points for Saturn with metre-level accuracy. The ephemeris INPOP19a, including this new dataset, provides an estimated mass for the trans-Neptunian object rings of (0.061 ± 0.001)M⊕.

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36

Standish, E. M. "Dynamical Reference Frame — Current Relevance and Future Prospects". International Astronomical Union Colloquium 180 (marzo de 2000): 120–26. http://dx.doi.org/10.1017/s025292110000021x.

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AbstractPlanetary and lunar ephemerides are no longer used for the determination of inertial space. Instead, the new fundamental reference frame, the ICRF, is inherently less susceptible to extraneous, non-inertial rotations than would be a dynamical reference frame determined by the ephemerides. Consequently, the ephemerides are now adjusted onto the ICRF, and they are fit to two modern, accurate observational data types: ranging (radar, lunar laser, spacecraft) and VLBI (of spacecraft near planets).The uncertainties remaining in the inner planet ephemerides are on the order of 1 kilometer, both in relative positions between the bodies and in the orientation of the inner system as a whole. The predictive capabilities of the inner planet ephemerides are limited by the uncertainties in the masses of many asteroids. For this reason, future improvements to the ephemerides must await determinations of many asteroid masses. Until then, it will be necessary to constantly update the ephemerides with a continuous supply of observational data.

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37

Fienga, A., L. Bigot, D. Mary, P. Deram, A. Di Ruscio, L. Bernus, M. Gastineau y J. Laskar. "Evolution of INPOP planetary ephemerides and Bepi-Colombo simulations". Proceedings of the International Astronomical Union 15, S364 (octubre de 2021): 31–51. http://dx.doi.org/10.1017/s1743921321001277.

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AbstractWe give here a detailed description of the latest INPOP planetary ephemerides INPOP20a. We test the sensitivity of the Sun oblateness determination obtained with INPOP to different models for the Sun core rotation. We also present new evaluations of possible GRT violations with the PPN parameters β, γ and . With a new method for selecting acceptable alternative ephemerides we provide conservative limits of about 7.16 × 10-5 and 7.49 × 10-5 for β-1 and γ-1 respectively using the present day planetary data samples. We also present simulations of Bepi-Colombo range tracking data and their impact on planetary ephemeris construction. We show that the use of future BC range observations should improve these estimates, in particular γ. Finally, interesting perspectives for the detection of the Sun core rotation seem to be reachable thanks to the BC mission and its accurate range measurements in the GRT frame.

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38

Standish, E. M. "Linking the Dynamical Reference frame to the ICRF". Highlights of Astronomy 11, n.º 1 (1998): 310–12. http://dx.doi.org/10.1017/s1539299600020839.

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AbstractThe latest JPL planetary and lunar ephemerides, DE405, are referenced to the International Celestial Reference Frame (ICRF) with an accuracy that approaches 1 mas for the four innermost planets, the sun, and the moon. This has been accomplished mainly by 18 VLBI observations of the Magellan Spacecraft in orbit around Venus. The ephemeris of Jupiter, however, is not well-determined since the various observations are not consistent within each other. The outer four planets continue to rely almost entirely upon optical observations; their ephemeris uncertainties lie in the 100-200 mas range.

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39

Marc’hadour, Germain. "Ephemerides moreanae". Moreana 24 (Number 95-9, n.º 3-4 (diciembre de 1987): 207–16. http://dx.doi.org/10.3366/more.1987.24.3-4.50.

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40

O’Neill, Patrick y Germain Marc’hadour. "Ephemerides Moreanae". Moreana 27 (Number 103), n.º 3 (septiembre de 1990): 101–12. http://dx.doi.org/10.3366/more.1990.27.3.22.

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41

Bejczy, István y Germain Marc’hadour. "Ephemerides Morerasmiennes". Moreana 29 (Number 110), n.º 2 (junio de 1992): 96. http://dx.doi.org/10.3366/more.1992.29.2.20.

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42

Lederle, T., B. L. Morando, V. K. Abalakin, S. Aoki, R. L. Duncombe, J. H. Lieske, A. Orte et al. "4. Ephemerides". Transactions of the International Astronomical Union 19, n.º 1 (1985): 1–6. http://dx.doi.org/10.1017/s0251107x00006052.

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The period of this Report includes 1984 January 1, the date which was probably the most drastic caesura in the history of astronomical almanacs. It seemed, therefore, appropriate to concentrate here to the general aspects rather than to describe the works going on at the particular almanac offices. It is, however, hoped that the past years with their developments and changes will be followed by a period of consolidation and continuity. This would be also of great benefit for the users of the almanacs who still need some time for getting accustomed to so many innovations.

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43

Fukushima, Toshio. "Time ephemeris and general relativistic scale factor". Proceedings of the International Astronomical Union 5, S261 (abril de 2009): 89–94. http://dx.doi.org/10.1017/s1743921309990202.

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AbstractTime ephemeris is the location-independent part of the transformation formula relating two time coordinates such as TCB and TCG (Fukushima 1995). It is computed from the corresponding (space) ephemerides providing the relative motion of two spatial coordinate origins such as the motion of geocenter relative to the solar system barycenter. The time ephemerides are inevitably needed in conducting precise four dimensional coordinate transformations among various spacetime coordinate systems such as the GCRS and BCRS (Soffelet al. 2003). Also, by means of the time average operation, they are used in determining the information on scale conversion between the pair of coordinate systems, especially the difference of the general relativistic scale factor from unity such asLC. In 1995, we presented the first numerically-integrated time ephemeris, TE245, from JPL's planetary ephemeris DE245 (Fukushima 1995). It gave an estimate ofLCas 1.4808268457(10) × 10−8, which was incorrect by around 2 × 10−16. This was caused by taking the wrong sign of the post-Newtonian contribution in the final summation. Four years later, we updated TE245 to TE405 associated with DE405 (Irwin and Fukushima 1999). This time the renewed vale ofLCis 1.48082686741(200) × 10−8Another four years later, by using a precise technique of time average, we improved the estimate of Newtonian part ofLCfor TE405 as 1.4808268559(6) × 10−8(Harada and Fukushima 2003). This leads to the value ofLCasLC= 1.48082686732(110) × 10−8. If we combine this with the constant defining the mean rate of TCG-TT,LG= 6.969290134 × 10−10(IAU 2001), we estimate the numerical value of another general relativistic scale factorLB= 1.55051976763(110) × 10−8, which has the meaning of the mean rate of TCB-TT. The main reasons of the uncertainties are the truncation effect in time average and the uncertainty of asteroids' perturbation. The former is a natural limitation caused by the finite length of numerical planetary ephemerides and the latter is due to the uncertainty of masses of some heavy asteroids. As a compact realization of the time ephemeris, we prepared HF2002, a Fortran routine to compute approximate harmonic series of TE405 with the RMS error of 0.446 ns for the period 1600 to 2200 (Harada and Fukushima 2003). It is included in the IERS Convention 2003 (McCarthy and Petit 2003) and available from the IERS web site;http://tai.bipm.org/iers/conv2003/conv2003_c10.html.

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44

Sharp, Philip W. "High order explicit Runge-Kutta pairs for ephemerides of the Solar System and the Moon". Journal of Applied Mathematics and Decision Sciences 4, n.º 2 (1 de enero de 2000): 183–92. http://dx.doi.org/10.1155/s1173912600000146.

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Numerically integrated ephemerides of the Solar System and the Moon require very accurate integrations of systems of second order ordinary differential equations. We present a new family of 8-9 explicit Runge-Kutta pairs and assess the performance of two new 8-9 pairs on the equations used to create the ephemeris DE102. Part of this work is the introduction of these equations as a test problem for integrators of initial value ordinary differential equations.

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45

Belikov, M. L., V. N. Boyko, N. I. Glebova, G. I. Eroshkin, L. I. Rumyantseva, M. L. Sveshnikov, E. S. Sveshnikova et al. "The Main Stages of the Construction of AE89—The Numerical Ephemeris of the Planets and the Moon". Symposium - International Astronomical Union 141 (1990): 183–85. http://dx.doi.org/10.1017/s0074180900086733.

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The realization of theoretical and applied researches in the domain of ephemeris astronomy, connected with analysis of precision of existing planetary and lunar theories, the construction of an inertial coordinate system and investigation of physical properties of space-time, necessitated the elaboration in ITA of the numerical theory of the motion of heavenly bodies suitable for calculation of high-precision ephemerides at large time-spans, and fit also for the maintenance of space experiments.

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46

Pitjeva, E. V. "Use of optical and radio astrometric observations of planets, satellites and spacecraft for ephemeris astronomy". Proceedings of the International Astronomical Union 3, S248 (octubre de 2007): 20–22. http://dx.doi.org/10.1017/s1743921308018565.

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AbstractDifferent types of radiometric observations of planets and spacecraft, as well as optical data used for constructing modern high-precision planet ephemerides are presented. New mass values for planets and asteroids are given. The IAA RAS EPM ephemerides (Ephemerides ofPlanets and theMoon) are the basis for the Russian “Astronomical Yearbook” and are used in the navigation program “GLONASS” and the cosmic program “Phobos-Grunt”.

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47

Pitjeva, E. V. "EPM ephemerides and relativity". Proceedings of the International Astronomical Union 5, S261 (abril de 2009): 170–78. http://dx.doi.org/10.1017/s1743921309990342.

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AbstractIn the seventies of the last century the EPM ephemerides (Ephemerides of Planets and the Moon) of IAA RAS originated and have been developed since that time. These ephemerides are based upon relativistic equations of motion of celestial bodies and light rays and upon relativistic time scales. The updated model of EPM2008 includes the new values of planet masses and other constants, the improved dynamical model with adding Trans–Neptunian Objects and the expanded database (1913–2008). More than 260 parameters have been determined while improving the planetary part of EPM2008 to 550000 observations. EPM2008 have been oriented to ICRF by including into the total solution the VLBI data of spacecraft near the planets. The real uncertainty of EPM ephemerides has been checked by comparison with the JPL's DE ephemerides. Some estimates of the post–model parameters have been obtained: |1−β| < 0.0002, |1−γ| < 0.0002, /G = (−5.9±4.4) ⋅ 10−14 per year, the statistic zero corrections to the planet perihelion advances.

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48

Marc’hadour, Germain. "Ephemerides A.D. 1986". Moreana 24 (Number 94), n.º 2 (junio de 1987): 109–17. http://dx.doi.org/10.3366/more.1987.24.2.26.

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49

Bloch, René. "Ephemerides Theologiae Lovanienses". Journal for the Study of Judaism 46, n.º 4-5 (25 de noviembre de 2015): 582–83. http://dx.doi.org/10.1163/15700631-12340116.

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50

Krasinsky, George A., Toshio Fukushima, Jean Chapront, John A. Bangert, Jean Chapront, Catherine Y. Hohenkerk, George H. Kaplan et al. "COMMISSION 4: EPHEMERIDES". Proceedings of the International Astronomical Union 3, T26B (diciembre de 2007): 79–83. http://dx.doi.org/10.1017/s1743921308023697.

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This business meeting was held from 16:00 to 17:30. Toshio Fukushima and George Kaplan were welcomed as the next president and vice-president, respectively. The following, in no particular order, are the summary reports from the various offices. The full versions will be made available on the Commission 4 website at <http://iau-comm4.jpl.nasa.gov/>.

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