scholarly journals The Reference Frame Determined From the Observation of Minor Planets by Hipparcos

1990 ◽  
Vol 141 ◽  
pp. 329-336
Author(s):  
B. Morando ◽  
A. Bec-Borsenberger
Keyword(s):  
Reference Frame ◽  
High Precision ◽  
Reference System ◽  
Initial Position ◽  
Minor Planet ◽  
Minor Planets ◽  
The Moon ◽  
Phase Effect ◽  
The Earth ◽  
A Minor

The observation of minor planets by Hipparcos offers the opportunity to obtain high precision positions for some minor planets. About fifty minor planets are on the programme. Their ephemerides had to be improved in order to reach a precision of 1 arsec and occultations by the Earth and the Moon had to be predicted.From the position of a minor planet on reference great circles at different times better values of the initial position and velocity will be deduced but the reduction of the observations of the minor planets have to take into account the displacement of the photocentre relative to the centre which is due to the shape, the phase effect and the scattering properties of the surface. For some very small planets considered as star like this diplacement will be small and the precise positions obtained will allow to position the dynamical reference system relative to the Hipparcos system. For the bigger minor planets the observations by Hipparcos may give informations on the shape and scattering properties of the surface.

scholarly journals Improving the dynamical reference frame through minor planet orbit correction using crossing point observations

1988 ◽  
Vol 128 ◽  
pp. 55-60
Author(s):  
Arthur L. Whipple ◽  
Raynor L. Duncombe ◽  
Paul D. Hemenway
Keyword(s):  
Computer Program ◽  
Reference Frame ◽  
Reference System ◽  
Hubble Space Telescope ◽  
Simulated Data ◽  
Minor Planet ◽  
Minor Planets ◽  
Space Telescope ◽  
Orbit Correction ◽  
Crossing Point

We have begun a program to establish a dynamical reference frame based on the motions of minor planets. The program will utilize observations from the Hubble Space Telescope, and will ultimately tie the HIPPARCOS reference system to a dynamical base. Thirty-four minor planets, 20 of which are suitable for observation with the Hubble Space Telescope, have been selected. Ground based observations, particularly crossing-point observations with long focus reflectors, have been initiated.A computer program to simultaneously solve for the corrections of the orbits of the 34 minor planets including the crossing-point observations, was successfully run. The observations are treated by the method of W. H. Jeffreys. Using simulated data, solutions with and without crossing point observations demonstrate the value of those observations to produce a homogeneous and coherent set of results.

scholarly journals Construction of a planetary solution with the help of an n-body program and analytical complements

1986 ◽  
Vol 114 ◽  
pp. 69-69
Author(s):  
P. Bretagnon
Keyword(s):  
Numerical Integration ◽  
Relativistic Effects ◽  
Analytical Form ◽  
Minor Planets ◽  
The Sun ◽  
The Moon ◽  
The Earth ◽  
Planetary Theories

Up to now we have been dealing with the construction of entirely analytical planetary theories such as VS0P82 (Bretagnon, 1982) and T0P82 (Simon, 1983). These theories take into account the whole of the newtonian perturbations of nine point masses: the Sun, the Earth-Moon barycenter, the planets Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune. They also take into account perturbations due to some minor planets, to the action of the Moon and the relativistic effects. The perturbations of these last three types are in a very simple way under analytical form but they considerably increase the computations when introduced in the numerical integration programs.

scholarly journals The reference frame of the ephemerides

1988 ◽  
Vol 128 ◽  
pp. 49-53 ◽  
Author(s):  
E. M. Standish ◽  
X. X. Newhall ◽  
J. G. Williams ◽  
J. O. Dickey
Keyword(s):  
Least Squares ◽  
Reference Frame ◽  
Reference System ◽  
The Moon ◽  
Least Squares Adjustment

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.

scholarly journals Hipparcos Photometry of Minor Planets

1993 ◽  
Vol 156 ◽  
pp. 25-30
Author(s):  
B. Morando ◽  
F. Mignard
Keyword(s):  
Absolute Magnitude ◽  
Apparent Magnitude ◽  
Minor Planets ◽  
The Sun ◽  
Phase Effect ◽  
The Earth ◽  
Main Detector

In addition to its astrometric capabilities the Hipparcos main detector proves to be a good phototometer. The main features of the photometric reduction applied to minor planets are outlined. The apparent magnitude measured by Hipparcos is transformed into absolute magnitude after corrections for the distance to the sun, the earth and for the phase effect, are applied. We show that the remaining signal contains information on the rotational properties of the planets.

scholarly journals Reference frames, gauge transformations and gravitomagnetism in the post-Newtonian theory of the lunar motion

2009 ◽  
Vol 5 (S261) ◽  
pp. 40-44 ◽  
Author(s):  
Yi Xie ◽  
Sergei Kopeikin
Keyword(s):  
Solar System ◽  
Reference Frame ◽  
Reference Frames ◽  
Laser Ranging ◽  
The Moon ◽  
Field Equations ◽  
Lunar Laser Ranging ◽  
Metric Tensor ◽  
The Earth ◽  
Lunar Motion

AbstractWe construct a set of reference frames for description of the orbital and rotational motion of the Moon. We use a scalar-tensor theory of gravity depending on two parameters of the parametrized post-Newtonian (PPN) formalism and utilize the concepts of the relativistic resolutions on reference frames adopted by the International Astronomical Union in 2000. We assume that the solar system is isolated and space-time is asymptotically flat. The primary reference frame has the origin at the solar-system barycenter (SSB) and spatial axes are going to infinity. The SSB frame is not rotating with respect to distant quasars. The secondary reference frame has the origin at the Earth-Moon barycenter (EMB). The EMB frame is local with its spatial axes spreading out to the orbits of Venus and Mars and not rotating dynamically in the sense that both the Coriolis and centripetal forces acting on a free-falling test particle, moving with respect to the EMB frame, are excluded. Two other local frames, the geocentric (GRF) and the selenocentric (SRF) frames, have the origin at the center of mass of the Earth and Moon respectively. They are both introduced in order to connect the coordinate description of the lunar motion, observer on the Earth, and a retro-reflector on the Moon to the observable quantities which are the proper time and the laser-ranging distance. We solve the gravity field equations and find the metric tensor and the scalar field in all frames. We also derive the post-Newtonian coordinate transformations between the frames and analyze the residual gauge freedom of the solutions of the field equations. We discuss the gravitomagnetic effects in the barycentric equations of the motion of the Moon and argue that they are beyond the current accuracy of lunar laser ranging (LLR) observations.

scholarly journals Dynamical Reference Frames in the Planetary and Earth-Moon Systems

1990 ◽  
Vol 141 ◽  
pp. 173-182
Author(s):  
E. M. Standish ◽  
J. G. Williams
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Optical Data ◽  
Laser Ranging ◽  
The Moon ◽  
Lunar Laser Ranging ◽  
The Earth ◽  
Lunar Laser ◽  
Mariner 9 ◽  
Radar Ranging

We summarize our previous estimates of the accuracies of the ephemerides. Such accuracies determine how well one can establish the dynamical reference frame of the ephemerides. Ranging observations are the dominant data for the inner four planets and the Moon: radar-ranging for Mercury and Venus; Mariner 9 and Viking spacecraft-ranging for the Earth and Mars; lunar laser-ranging for the Moon. Optical data are significant for only the five outermost planets. Inertial mean motions for the Earth and Mars are determined to the level of 0.″003/cty during the time of the Viking mission; for Mars, this will deteriorate to 0.″01/cty or more after a decade or so; similarly, the inclination of the martian orbit upon the ecliptic was determined by Viking to the level of 0.″001. Corresponding uncertainties for Mercury and Venus are nearly two orders of magnitude larger. For the lunar mean motion with respect to inertial space, the present uncertainty is about 0.″04/cty; at times away from the present, the uncertainty of 1′/cty2 in the acceleration of longitude dominates. The mutual orientations of the equator, ecliptic and lunar orbit are known to 0.″002. The inner four planets and the Moon can now be aligned with respect to the dynamical equinox at a level of about 0.″005.

scholarly journals A Note on the Astrometric Precision of Minor Planet Observations

1991 ◽  
Vol 127 ◽  
pp. 327-330
Author(s):  
D. Pascu
Keyword(s):  
Reference Frame ◽  
Lower Limit ◽  
Satellite Observations ◽  
Minor Planet ◽  
Minor Planets ◽  
Crossing Point

AbstractFor years, interest in precise positions of minor planets has centered on tying the dynamical reference frame with the stellar frame and determining catalog zone errors. Photographic methods are generally used in obtaining observed spherical equatorial coordinates (R.A., Dec.) or crossing-point observations. Estimates of the external precision of the equatorial coordinates are overly pessimistic, while those for crossing-point observations, too optimistic.It is estimated that equatorial positions for the brighter (m < 11) minor planets can be determined with an external precision not worse than +/−0.2 arcsec (m.e.), and perhaps as low as +/−0.1 arcsec (m.e.), depending on the reference catalog zonal errors.Intersatellite observations are a type of crossing-point observation in which the images of two different objects appear in the same exposure. This is the most precise type of crossing-point observation and gives an estimate for the lower limit to the external precision of this observation type. Recent studies of satellite observations indicate that this lower limit is in the +/−0.05 to +/−0.08 arcsec (m.e.) range.

scholarly journals Amateur Astronomers and the IAU Central Bureau for Astronomical Telegrams and Minor Planet Center

1988 ◽  
Vol 98 ◽  
pp. 64-76 ◽  
Author(s):  
Brian G. Marsden
Keyword(s):  
Minor Planet ◽  
Central Bureau ◽  
Minor Planets ◽  
X Ray ◽  
The Earth ◽  
International Astronomical ◽  
Set Up ◽  
The One ◽  
Natural Satellites ◽  
To Receive

Of all the sections of the International Astronomical Union the Central Bureau for Astronomical Telegrams is undoubtedly the one that most concerns amateur astronomers. Just about anybody in the world with at least some familiarity with the sky has the potential to discover (or to think he or she has discovered) a comet or nova. If the object is real and sufficiently bright, it is very probably already known. Somebody has to be the first discoverer of every comet or nova, however, and soon after the IAU was established in 1919 it set up the Central Bureau to receive and to disseminate to the astronomical community news of such discoveries. Discoveries of supernovae in other galaxies, natural satellites of the planets, erupting x-ray sources and transient features on the planets are also dealt with by the Central Bureau, which since 1965 has operated at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts. The Central Bureau handles unusual minor planets in the vicinity of the earth, although the thousand or more ordinary minor planets routinely discovered each year (and with which amateurs are being increasingly involved) are more appropriately the province of the Minor Planet Center, set up by the IAU in 1947 and since 1978 also operated at the Smithsonian Astrophysical Observatory. About one-quarter of the subscribers to the various services of the Central Bureau and/or the Minor Planet Center are individual amateur astronomers or organizations of amateurs.

scholarly journals On the Coordinate Systems Used in the Study of Polar Motion

1979 ◽  
Vol 82 ◽  
pp. 89-101
Author(s):  
E. P. Fedorov
Keyword(s):  
Reference Frame ◽  
Reference System ◽  
Polar Motion ◽  
Earth’S Rotation ◽  
Coordinate Systems ◽  
Earth's Rotation ◽  
The Earth ◽  
Rotation Of The Earth ◽  
Selection Of

IAU Symposium No. 78 “Nutation and the Rotation of the Earth” held in Kiev in 1977 revealed a certain lack of precision in the fundamental concepts and some looseness of terminology employed in the treatment of this problem. When talking about polar motion we should give, first of all, rigorous conceptual definitions of both the pole and a reference frame in which it moves. The selection of a reference system was the topic of an IAU Colloquium held in Torun in 1974. Although the discussion there was thorough and comprehensive, it did not result in the removal of all ambiguities which have tarnished discussion of the problems in the understanding of the Earth's rotation.

The Approach of Improvement to Stellar Coordinate

1991 ◽  
Vol 127 ◽  
pp. 299-302
Author(s):  
W.Z. Ma
Keyword(s):  
Zero Point ◽  
Minor Planet ◽  
New Method ◽  
Planetary Orbit ◽  
Lower Latitude ◽  
Minor Planets ◽  
Meridian Circle ◽  
Precise Result ◽  
Electronic Imaging ◽  
A Minor

AbstractThis article presents a new method for observing minor planets. The observation is operated with a photo–electronic imaging devise CCD and a lower latitude meridian circle.The CCD is mainly used except it is during the favourable opposition of the minor planet when the meridian circle is mainly used in this method. The method can improve precision of observation of planetary position and enlarge scope of observation of planetary orbit. Therefore, the measured precision of zero point of stellar coordinate could be increased. The key of succeeding is that more precise result is got using the CCD.The experiment in this article indicates that this method is a good way:While a minor planet and calibration stars locate in the same image of the CCD, the measured precisions of the minor plant areσα = ±0″.03, σ´ ±0″.035;While the minor planet and calibration stars are located in different images of the CCD, the precisions areσα = ±0″.06, σδ = ±0″.08.

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