Titlebook: Reports on Astronomy; Derek McNally (General Secretary of the Union) Book 1991 Springer Science+Business Media Dordrecht 1991 Astrometry.C

表状态

Positions and Motions of Minor Planets, Comets and Satellites (Positions et Mouvements Des Petites ions as well as refined theoretical models of the motions in the solar system. Among many other achievements, the secular acceleration of Phobos was accurately measured and the dynamical analysis of the ring-like arcs at Neptune has just begun.

错事

易弯曲

Aromatic

弓箭

ns Reports on Astronomy, prepared by each Commission President. The intention is to summarize the astronomical results that have affected the work of the Commission since the production of the previous Reports up to a time which is about one year prior to the General Assembly...Volume B. is produced

拍翅

富饶

Instruments And Techniques (Instruments et Techniques), optical fibers, particularly in the area of multiple-object spectroscopy, has continued to grow. Several telescopes can now be operated remotely and the control systems of new telescopes are being designed to facilitate remote operation.

来自于

Positional Astronomy (Astronomie de Position), satellite HIPPARCOS, as are described in this report. IAU conferences of interest to the commission and its membership held during the past triennium include the following: . was held at Belgrade in September 1987. H. K. Eichhorn, C. A. Murray, and A. R. Upgren are editing the proceedings.

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Earth Rotation (Rotation de la Terre),ame is consistent with the FK5 within the uncertainties of the latter (0.04″). The IERS Standards (1989) which contain the current best estimates of astronomical models and constants are used in many fields of astronomy and geodesy.

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Ephemerides (Ephemerides),omical constants, nutation of the Earth, time and reference frames/origin. The purpose is to define a future reference system and resolve some of the difficulties that occur in the system. It is anticipated that this Working Group will develop recommendations for consideration at the 21st General Assembly of the IAU.