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Modern CCD Observations of Moving Celestial Objects: Algorithms and Software for Interactive Processing Next: DASH - Distributed Analysis System Hierarchy
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Bykov, O. P. 1999, in ASP Conf. Ser., Vol. 172, Astronomical Data Analysis Software and Systems VIII, eds. D. M. Mehringer, R. L. Plante, & D. A. Roberts (San Francisco: ASP), 353

Modern CCD Observations of Moving Celestial Objects: Algorithms and Software for Interactive Processing

Oleg Bykov
Pulkovo Astronomical Observatory, 196140, Pulkovskoe shosse 65, St. Petersburg, Russia

Abstract:

The problems of observing asteroids using CCDs are discussed. Their identifications and orbit determinations are considered. Also, a method for quality control of CCD observations is suggested.

1. Introduction

CCD observations of the Small Solar System bodies are rapidly progressing. Every month professional astronomers together with an increasing number of amateurs obtain several hundreds of thousands of asteroid positions and send them to the International Minor Planet Center. Everyone who observes a celestial object using a CCD detects moving celestial objects as a ``by product''. Usually, tests of such observations and identifications of moving objects are not produced by these observers.

Obviously, it would be advantageous for the MPC to receive observations of asteroids with their identifications. Thus, it is necessary to provide astronomers, especially amateurs, with a package for quick solutions to the control and identification problems immediately after CCD observations have been made.

The original algorithms and software were developed in the Pulkovo Astronomical Observatory to solve the following problems:

test of any positional observations of celestial bodies, artificial and natural, by analyzing the first and second derivatives of the orbital or approximate coordinate (O-C) residuals,
calculation of the apparent motion parameters (namely topocentric angular velocity, $\mu$ , angular acceleration, $\dot\mu$ , positional angle, $\psi$ , and curvature, C of the trajectory) by using the spherical coordinate approximation,
preliminary orbit determination of a celestial body observed on a super short arc of its topocentric trajectory; we use the Classical Laplace Method and the new Apparent Motion Parameters Method created at Pulkovo Observatory for the calculation of the circular and the elliptic orbital elements,
an identification of the observed celestial body using of known orbital catalogues or our own orbit determinations,
our own ephemeris service for known and unknown celestial objects from artificial satellites up to the Kuiper Belt asteroids.

We have had much success with the practical applications of our algorithms and software. We use the ``CERES Plus'' package and ``LAPLACE'' software in our analysis of moving celestial bodies. The algorithms and major results were published in Russian (Bykov 1989, 1996; Kiselev & Bykov 1973, 1976). Several examples are given here in the Tables.

We hope that our investigations may be useful for near-Earth space control and also for searches of the moving celestial objects through analysis of old and new CCD frames obtained at any amateur or professional astronomical observatory.

2. Examples

$\begin{table} \begin{center} \caption {Accuracy of CCD Observations. }\ \\ \beg... ...& 0.07 & 0.04& \\ &&&&&&&&&\\ \hline \par\end{tabular}\end{center}\end{table}$
A sample of accuracies of CCD observations of the numbered minor planets reported to International Minor Planets Center during 1995-1996.

The CERES software package, which was developed at the former Institute of Theoretical Astronomy (in Russia), was used to calculate (O-C)-differences for nearly 700 minor planets which were observed irregularly and quasi-simultaneously in 1995-96 using CCDs as well as photography at nearly 50 observatories. The accuracy of observations was estimated by means of dispersion of average (O-C) for each type of observations obtained by each telescope. Some results are given in Table 1. Here, the term ``Internal accuracy'' (int.) indicates that an estimation was derived from analysis of minor planet positions obtained in one night for each of them. ``External accuracy" (ext.) indicates that observations made during several successive nights were used only. In the columns 8 and 9, where the main results of the accuracy investigations are presented, the values below accuracy values are the mean errors of our estimates.

3. Example of Accuracies of Modern CCD Observations.

$\begin{table} \begin{center} \caption {(O--C) residuals for the NMP 3035 Chamber... ...& & $\pm 0.12$& & $ \pm 0.09$& & \\ \hline \end{tabular}\end{center}\end{table}$
(O-C) residuals for the NMP 3035 Chambers observed by two telescopes (obs. codes 699,704) with a CCD during a single night.

$\begin{table} \begin{center} \caption {Error Estimation. }\ \\ \begin{tabular}{... ...$\ &$ $&$ $&$ $&$ $&$ $&$ $\ \\ \par\hline \end{tabular}\end{center}\end{table}$
The first derivatives and estimation of accuracy of data presented in Table 2.

Parameters $\dot\alpha$ , $\dot\delta$ , their accuracy characteristics (in percents) and differences (O - C) which may be obtained by linear approximation of the coordinate sets presented in Table 2 and by comparison with the exact values given by the CERES software.

$\begin{table} \begin{center} \caption {Apparent Motion Parameters. }\ \\ \vskip... ...576 $\ &$ 3.6675 $\ &$ 1.6718 $\ \\ \hline \end{tabular}\end{center}\end{table}$
Calculation of the geocentric differential parameters for some numbered minor planets and comparison with the actual parameters obtained with a processing of positional observations.

Table 4 shows apparent motion parameters $\alpha, \delta, \mu, \dot\mu, \psi, C$ are reliable and can be calculated from the modern position observations. They allow us to obtain the preliminary orbit elements of asteroid.

Acknowledgments

We thank the LOC of the ADASS'98 conference for hospitality and financial support.

References

Bykov, O. P. 1989, Problems of Universe Investigations, 12, 328

$\ibid$ , 1996, in Proc. of IAU Symp. 172, Dynamics, Ephemerides and Astrometry of the Solar System, ed. S. Ferraz-Mello & J.-E. Arlot (Dordrecht: Kluwer), 458

Kiselev, A. A. & Bykov, O. P. 1973, Sov. Aston. J., 50, 1298

$\ibid$ , 1976, Sov. Aston. J., 53, 879

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