A discussion on orbital analysis - Determination of Love’s number from satellite observations

The structure of theories used in determining the gravitational field from the perturbations of orbits of artificial satellites is discussed and it is shown how it corresponds to the fact that small departures from a Keplerian ellipse are readily observed. Some current problems are mentioned. Statistical problems in the estimation of parameters of the field from orbital data are considered and recent estimates are summarized

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A discussion on orbital analysis - A brief survey of satellite orbit determination

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1967.0032 ◽

1967 ◽

Vol 262 (1124) ◽

pp. 71-78

Keyword(s):

Orbit Determination ◽

Accurate Determination ◽

Solar Radiation Pressure ◽

Satellite Orbit ◽

Dynamical Theory ◽

Satellite Orbits ◽

Perturbation Techniques ◽

The Earth ◽

Orbital Analysis

The accurate determination of satellite orbits depends on an adequate accumulation of observations, a sound dynamical theory and a fairly sophisticated sequence of numerical computations. The particular patterns of observation, theory and computation are considered in relation to the objectives of orbit determination. Factors to be taken into account are the type, accuracy and spread of observations; perturbations of the orbit due to air drag, attraction of the Earth, Moon, and Sun, and solar radiation pressure; and the speed and cost of available computers. These factors, together with the overall objectives, determine the main features of the computation; whether to use special or general perturbation techniques, what length of orbit arc to use, what parameters to determine and how to present the results.

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A discussion on orbital analysis - Recent developments in determination of the lunar gravitational field from satellite orbits

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1967.0042 ◽

1967 ◽

Vol 262 (1124) ◽

pp. 148-155 ◽

Cited By ~ 2

Keyword(s):

Gravitational Field ◽

Los Angeles ◽

Hydrostatic Equilibrium ◽

University Of California ◽

Satellite Orbits ◽

The Earth ◽

Recent Developments ◽

Lunar Topography ◽

Orbital Analysis

The initial determinations of the variations in the lunar gravitational field are appreciably milder than those of the Earth in the sense of stress-implication, indicating a state closer to hydrostatic equilibrium. The variations determined also have a considerable correlation with the lunar topography, indicating a shallower origin than the Earth’s variations. The data are still insufficient to determine firmly the lunar oblateness, and thus help resolve the problem of the Moon’s moment of inertia. This paper is being issued as Publication No. 559 of the Institute of Geophysics and Planetary Physics, University of California, Los Angeles.

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HADIS KURAIB DALAM KONSEP RUKYATUL HILAL

JURNAL PENELITIAN ◽

10.28918/jupe.v13i2.723 ◽

1970 ◽

Vol 13 (2) ◽

Author(s):

Muslih Husein

Keyword(s):

The West ◽

The Earth ◽

New Moon ◽

The Republic

Hisab dan rukyat, hakikatnya, adalah cara untuk mengetahui pergantian bulan. Kajian ini memperlihatkan beberapa temuan. Pertama, korelasi antara hadis Kuraib dan terjadinya perbedaan penetapan awal Ramadan, Syawal, dan Dzul Hijjah di Indonesia. Kementerian Agama Republik Indonesia telah menetapkan bahwa Indonesia secara keseluruhan menjadi satu wilayah hukum (wilayatul hukmi). Kedua, tentang keberhasilan rukyat al-hilal di satu kawasan yang diberlakukan bagi kawasan lain di muka bumi. Perlu diketahui bersama bahwa visibilitas pertama hilal tidak meliputi seluruh muka bumi pada hari yang sama, melainkan membelahnya menjadi dua bagian: (1) bagian sebelah Barat yang dapat melihat hilal dan (2) bagian sebelah Timur yang tidak dapat melihat hilal.Hisab and rukyat is a way to know the turn of the month. This study shows several findings. First is the correlation between Kuraib traditions and differences in the determination of the beginning of Ramadan, Shawwal, and Dhul-Hijjah in Indonesia. Ministry of Religious Affairs of the Republic of Indonesia has stated that Indonesia as a whole into a single jurisdiction (wilayatul hukmi). Second, on the success rukyat alhilal in one area that applied to other regions of earth. Important to know that the first visibility of the new moon does not cover the entire face of the earth on the same day, but splitting it into two parts: (1) part of the West to see the new moon, and (2) part of the East were not able to see the new moon.

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