Raymond Mercier

The discussion centres around three topics, the zero point of the ayanaṃśa (precession for sidereal longitudes), the date of the Mahāsiddhānta, and the application of features of Indian parameters to the problem of Earth rotation.

An edition and translation of a Greek almanac for the year 1336, based on the unique MS Bayarischen Staatsbibliothek in Mǔnhen, Greek MS 525 fols.155-171. The almanac lists the daily positions of the sun, moon, and planets, together with astrological configurations. There is a full analysis of the astronomical content, and a comparison with late Is...

The Hall of Heavenly Records: Korean astronomical instruments and clocks 1380–1780. By NeedhamJoseph, Lu Gwei-djen, CombridgeJohn H. and MajorJohn S.. (Antiquarian Horological Society Monograph No. 25.) pp. xxii, 201, illus., front. Cambridge etc., Cambridge University Press, 1986. £25.00. - Volume 122 Issue 1 - Raymond Mercier

The purpose of this article is to develop the relation between the Standard Scheme and the trigonometrical models - that is, those based on the use of one or more epicycles -, one that situates the model in the interface between Babylonian and Greek astronomy.

In this paper a theory is given of statistical correlation in the complex amplitude of a scalar wave diffracted by an irregular object of limited extent. The theory is one-dimensional, and uses the Fresnel integral to calculate the amplitude at the receiver. Two well-known results appear as special cases. In the first the correlation function of th...

The theory of equilibrium black body radiation has been applied to an anisotropic medium, together with a special application to a magnetoionic medium. Numerical results are presented in a curve showing the angular spectrum in the `whistler mode' where X = 4, Y = 9 in the usual notation of magnetoionic theory. The flux per unit solid angle and unit...

Roger Billard, 29 August 1922 - 30 December 2000.

The calendar employed in inscriptions dated in the Era of the Province of Arabia has been determined hitherto in every feature except for the position of the leap year. That missing element is supplied here. The Era begins with the year counted from one on A.D. 106 Mar 22, and it is shown here that the leap years are the years numbered 2, 6, 10, et...

Critical edition and commentary of an astronomical Manual written by George Gemistus Pletho

Recent investigations of the astronomical work of the Byzantine Platonist George Gemistus Plethon provided the motivation, for Plethon's work encapsulated to many of the cross-currents flowing in astronomy in the early fifteenth century. At a time when the Byzantine world was in a state of collapse, and perhaps for that reason was more susceptible...

Sawai Jai Singh and his astronomy. By SharmaVirendra Nath. pp. xvi, 347, front., illus. Delhi, Motilal Banarsidass, 1995. Rs 245. - Volume 7 Issue 3 - Raymond Mercier

The canons of Sanskrit astronomy depend on mean motions which are normally postulated to refer to the central meridian of Ujjain. The present work is a statistical analysis of these mean motions designed to discover the optimum position of the meridian, by comparison with modern mean motions. This follows earlier work done by Billard in determining...

Questions of the meridian of reference are a matter of practical concern for any student of the tables of medieval astronomy. Not only are many tables related by a mere change of meridian, perhaps accompanying a change of language; but if one wishes to make a comparison between the table and the modern Fundamental Ephemeris, it is clearly necessary...

The Zij-i-Muhammed Shahi is a set of astronomical tables in Persian associated with Jai Singh Sawa'i (died 1743). They are usually represented as embodying the observational work done at the observatories of Delhi and Jaipur, under the direction of Jai Singh and Jagannatha. In this paper these Persian tables are analysed thoroughly, and their vario...

Antiquity - A Survey of the Almagest. By PedersenOlaf. Acta historica scientiarum naturalium et medicinalium, Edidit Bibliotheca Hauniensis, xxx. Odense: Odense University Press, 1974. Pp. 454. £20. - Volume 11 Issue 1 - Raymond Mercier

C V Heer London: Academic Press 1972 pp xvi + 602 price £18.50 This is a very ambitious work, claiming to present not only statistical thermodynamics ab initio, but a very wide variety of applications in substantial detail. The reviewer is however very disappointed with the entire work.

From the time of A macronryabhat under dota (ca AD 500) there appeared in India a series of Sanskrit treatises on astronomy. Written always in verse, and normally accompanied by prose commentaries, these served to create an Indian tradition of mathematical astronomy which continued into the 18th century. There are as well texts from earlier centuri...

We have made a fresh analysis of the problem of calculating the local electric field and defining the related polarization in a classical assembly of electrons and nuclei, a model which can serve to represent either the dielectric or plasma. In general the local field acting on an electron is defined as the change produced in the ensemble average f...

For the class of potentials vanishing beyond a certain point we have derived a new dispersion formula in which the scattering matrix S(k) is written as the ratio of two conditionally convergent partial fraction sums. The numerator displays the poles of S(k) at the complex eigenvalues kn and the denominator displays poles at -kn, the zeros of S(k)....

In this paper the spectrum of radio-frequency radiation from a fully ionized ion-electron plasma is calculated, starting from the dependence of the dipole moment on the particle-particle Coulomb fields. These Coulomb fields are shielded according to the usual dielectric constant theory. The acceleration of a particle by others of like species gives...

The propagation of a scalar wave is studied, after it has suffered changes of phase in its passage through an irregular refracting medium, such as the ionosphere. The rms phase fluctuations may be large; i.e. greater than one radian. The paper is in three parts. In the first, the receiver is at a great distance from the screen (Fraunhofer diffracti...

A scalar wave with random variations of amplitude and phase across the wave-front is assumed as a simple model of a radio wave after it has left the ionosphere. The second-order moments of the in-phase and quadrature components of the fluctuating part of the field are found using the Fresnel diffraction formula. It is assumed that these two compone...