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.

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 A New Concept of Constructing an Accurate Coordinate System From Ground-Based Optical Observations

1990 ◽  
Vol 141 ◽  
pp. 129-130
Author(s):  
Mao Wei ◽  
Hu Xiaochun ◽  
Guo Xinjian ◽  
Fan Yu
Keyword(s):  
Coordinate System ◽  
Reference System ◽  
Zero Point ◽  
Optical Observations ◽  
Minor Planets ◽  
Meridian Circle ◽  
Inertial Coordinate System ◽  
Low Latitude ◽  
Main Work ◽  
Set Up

Based on the expected precision and characteristics of the Low Latitude Meridian Circle (LLMC), and the development of CCD astrometry at Yunnan Observatory, an internally consistent and non-rotating optical celestial coordinate system can be set up through observations with the LLMC and CCDs. To obtain this goal, the main work we plan to do are (1) to establish a fundamental stellar reference system of several thousand stars based on the absolute obsrvations with the LLMC; (2) to provide the accurate zero-point corrections for the system from observations of minor planets with the LLMC and CCDs; (3) to determine the precessional rotation of the system with respect to an extragalactic reference system with the LLMC and CCDs, thus transforming the system into a quasi-inertial coordinate system; and (4) to obtain the atmospheric refraciton corrections from the observations with the LLMC.

Brief summary of Kleť photographic search programme for minor planets

1999 ◽  
Vol 173 ◽  
pp. 189-192
Author(s):  
J. Tichá ◽  
M. Tichý ◽  
Z. Moravec
Keyword(s):  
Ccd Camera ◽  
Minor Planet ◽  
Minor Planets ◽  
Main Belt

AbstractA long-term photographic search programme for minor planets was begun at the Kleť Observatory at the end of seventies using a 0.63-m Maksutov telescope, but with insufficient respect for long-arc follow-up astrometry. More than two thousand provisional designations were given to new Kleť discoveries. Since 1993 targeted follow-up astrometry of Kleť candidates has been performed with a 0.57-m reflector equipped with a CCD camera, and reliable orbits for many previous Kleť discoveries have been determined. The photographic programme results in more than 350 numbered minor planets credited to Kleť, one of the world's most prolific discovery sites. Nearly 50 per cent of them were numbered as a consequence of CCD follow-up observations since 1994.This brief summary describes the results of this Kleť photographic minor planet survey between 1977 and 1996. The majority of the Kleť photographic discoveries are main belt asteroids, but two Amor type asteroids and one Trojan have been found.

The O–C diagrams of minor planets − a new approach to modelling the rotation

1999 ◽  
Vol 173 ◽  
pp. 185-188
Author(s):  
Gy. Szabó ◽  
K. Sárneczky ◽  
L.L. Kiss
Keyword(s):  
Error Analysis ◽  
Time Dependence ◽  
Theoretical Work ◽  
Minor Planet ◽  
Minor Planets ◽  
New Approach ◽  
Preliminary Results ◽  
Ccd Observations

AbstractA widely used tool in studying quasi-monoperiodic processes is the O–C diagram. This paper deals with the application of this diagram in minor planet studies. The main difference between our approach and the classical O–C diagram is that we transform the epoch (=time) dependence into the geocentric longitude domain. We outline a rotation modelling using this modified O–C and illustrate the abilities with detailed error analysis. The primary assumption, that the monotonity and the shape of this diagram is (almost) independent of the geometry of the asteroids is discussed and tested. The monotonity enables an unambiguous distinction between the prograde and retrograde rotation, thus the four-fold (or in some cases the two-fold) ambiguities can be avoided. This turned out to be the main advantage of the O–C examination. As an extension to the theoretical work, we present some preliminary results on 1727 Mette based on new CCD observations.

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 TreeMerge: a new method for improving the scalability of species tree estimation methods

2019 ◽  
Vol 35 (14) ◽  
pp. i417-i426 ◽  
Author(s):  
Erin K Molloy ◽  
Tandy Warnow
Keyword(s):  
Large Scale ◽  
Species Tree ◽  
New Method ◽  
Divide And Conquer ◽  
Supplementary Information ◽  
Estimation Methods ◽  
Running Time ◽  
Tree Estimation ◽  
Computationally Intensive ◽  
A Minor

Abstract Motivation At RECOMB-CG 2018, we presented NJMerge and showed that it could be used within a divide-and-conquer framework to scale computationally intensive methods for species tree estimation to larger datasets. However, NJMerge has two significant limitations: it can fail to return a tree and, when used within the proposed divide-and-conquer framework, has O(n5) running time for datasets with n species. Results Here we present a new method called ‘TreeMerge’ that improves on NJMerge in two ways: it is guaranteed to return a tree and it has dramatically faster running time within the same divide-and-conquer framework—only O(n2) time. We use a simulation study to evaluate TreeMerge in the context of multi-locus species tree estimation with two leading methods, ASTRAL-III and RAxML. We find that the divide-and-conquer framework using TreeMerge has a minor impact on species tree accuracy, dramatically reduces running time, and enables both ASTRAL-III and RAxML to complete on datasets (that they would otherwise fail on), when given 64 GB of memory and 48 h maximum running time. Thus, TreeMerge is a step toward a larger vision of enabling researchers with limited computational resources to perform large-scale species tree estimation, which we call Phylogenomics for All. Availability and implementation TreeMerge is publicly available on Github (http://github.com/ekmolloy/treemerge). Supplementary information Supplementary data are available at Bioinformatics online.

A modified Runge-Kutta method

SIMULATION ◽  
1968 ◽  
Vol 10 (5) ◽  
pp. 221-223 ◽  
Author(s):  
A.S. Chai
Keyword(s):  
Error Estimate ◽  
Linear Combination ◽  
Experimental Results ◽  
The Other ◽  
New Method ◽  
Kutta Method ◽  
Starting Values ◽  
Runge Kutta Method ◽  
Runge Kutta ◽  
A Minor

It is possible to replace k2 in a 4th-order Runge-Kutta for mula (also Nth-order 3 ≤ N ≤ 5) by a linear combination of k1 and the ki's in the last step, using the same procedure for computing the other ki's and y as in the standard R-K method. The advantages of the new method are: It re quires one less derivative evaluation, provides an error estimate at each step, gives more accurate results, and needs a minor change to switch to the RK to obtain the starting values. Experimental results are shown in verification of the for mula.

scholarly journals 6. Astronomical Telegrams

1979 ◽  
Vol 17 (1) ◽  
pp. 13-14
Author(s):  
E. Roemer ◽  
B. G. Marsden
Keyword(s):  
Minor Planet ◽  
Central Bureau ◽  
Minor Planets ◽  
Business Operations ◽  
The Face ◽  
Careful Investigation

As noted below in the report of the Central Bureau, a number of changes have been introduced in the technical and business operations of the Bureau during the triennium. Some of the changes follow from the transfer of the IAU Minor Planet Center to the Smithsonian Astrophysical Observatory. For example the Minor Planet Circulars now offer an alternate avenue of publication for less time-urgent data concerning comets as well as minor planets. Changes at the communications center of the Smithsonian Astrophysical Observatory have made it less costly, as well as more efficient, for the Central Bureau to maintain its own communications equipment. At the same time, in the face of generally rising costs, and after careful investigation of alternatives, it has become necessary for users to assume an increased share in underwriting the operating expenses of the Bureau.

scholarly journals The Role of Observation With Horizontal Meridian Circle in China for Establishing an Inertial Frame

1990 ◽  
Vol 141 ◽  
pp. 142-142
Author(s):  
Li Zhi-gang ◽  
Qi Guan-Rong
Keyword(s):  
Inertial Frame ◽  
Minor Planets ◽  
Meridian Circle ◽  
Horizontal Meridian ◽  
Proper Motions ◽  
The Earth ◽  
The Future ◽  
History Of ◽  
Radio Stars

While HIPPARCOS is expected to measure positions and proper motions with more accuracy than those obtained by ground-based instruments, what can we do in the future for ground-based instruments? The observations with them still are important for establishing an inertial frame because of the long history of observations with them and improvements in the instruments. Moreover, it is necessary to have data of observations from them for research on problems related to the Earth. The horizontal meridian circle in China (DCMT) is expected to have advantage over the classical meridian circles. The DCMT will be assembled and tested this year. It should work in the following fields: (1) observing radio stars, (2) observation of minor planets, (3) absolute determinations of IRS.

scholarly journals DIVISION III / COMMISSION 15 / WORKING GROUP PHYSICAL STUDY OF MINOR PLANETS

2007 ◽  
Vol 3 (T26B) ◽  
pp. 131-132
Author(s):  
Walter F. Huebner ◽  
Alberto Cellino ◽  
Edward F. Tedesco ◽  
Dominique Bockelee-Morvan ◽  
Yuehua Ma ◽  
...  
Keyword(s):  
Physical Properties ◽  
Working Group ◽  
Business Meeting ◽  
Minor Planet ◽  
Minor Planets ◽  
Web Page ◽  
Division Iii ◽  
Physical Study

The meeting of the Physical Properties of the Minor Planets Working Group of IAU Commission 15 took place on 24 August, and was devoted to purely scientific matters, since other topics (organization of the Minor Planet WG, need of a new web page, election of the new chairman) had been already discussed during the business meeting of Commission 15, on 22 August. A brief summary of the talks given during the meeting is given in what follows.

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