scholarly journals Charles Rundle Davidson, 1875-1970

1971 ◽  
Vol 17 ◽  
pp. 193-194 ◽  
Keyword(s):  
Working Life ◽  
Relativity Theory ◽  
The Sun ◽  
Fine Weather ◽  
Royal Observatory ◽  
North Brazil ◽  
Star Images

Charles Rundle Davidson was born on 28 February 1875 and educated at Christ’s Hospital. He joined the staff of the Royal Observatory, which was then at Greenwich, on 10 March 1890, and was established as a Computer on 1 June 1896. He spent the whole of his working life at the Royal Observatory and retired on 31 August 1937, after more than 41 years’ established service. He died on 18 June 1970. When Davidson joined the staff of the Royal Observatory it was sharply divided into senior and junior ranks, and Davidson was a junior. Nevertheless he established a reputation for ability to handle equipment which was so great as to elevate him to the recognized position of the Observatory’s arbiter on all instrumental matters, and Dyson in particular relied on Davidson absolutely to supervise the later eclipse expeditions which Dyson made such a feature of the work of the Royal Observatory. In all, Davidson went on eight eclipse expeditions, of which the most famous was the eclipse of 1919, at which the Einstein effect, that is to say the deflexion of starlight passing the limb of the Sun, was first found. The whole matter was extremely important in establishing the relativity theory, and the expeditions of 1919, of which there were two from Greenwich, were given great prominence in Eddington’s writings. Eddington and Cottingham went to the island of Principe off the coast of Africa, and Davidson and Crommelin went to Sobral in North Brazil. At Principe the sky was partly clouded but some star images were found on the plates. At Sobral the observers were favoured with fine weather.

scholarly journals XXXIV. Observations on the transit of Ve­nus, June the 6th, 1761, made in Spital-Square; the longitude of which is 4' 11" west of the Royal Observatory at Green­wich, and the latitude 51° 31' 15" north

1761 ◽  
Vol 52 ◽  
pp. 182-183
Keyword(s):  
The Sun ◽  
Royal Observatory ◽  
The Mean ◽  
The Difference ◽  
Made In

Having measured the diameter of Venus, on the sun, three times, with the object-glass micrometer, the mean was found to be 58 seconds; and but 6/10 of a second, the difference of the extremes.

Desiderata for the Catalogue of Nearby Stars

1977 ◽  
Vol 35 ◽  
pp. 37-39
Author(s):  
W. Gliese
Keyword(s):  
The Sun ◽  
Royal Observatory ◽  
Trigonometric Parallaxes ◽  
Nearby Stars

In 1969 the second edition of the “Catalogue of Nearby Stars” was published. It contains 1529 single stars and systems with a total of 1890 components. The catalogue lists all stars with parallaxes equal to or larger than 0.”045. Only 1049 of these objects are nearer than 20 pc. The “Catalogue of Stars within 25 pc of the Sun”, published 1970 in the Royal Observatory Annals No. 5 consists of 1744 systems of which 1566 trigonometric parallaxes.

scholarly journals II. On a supposed periodicity in the elements of terrestrial mag­netism, with a period of 26 1/3 days

1872 ◽  
Vol 20 (130-138) ◽  
pp. 308-312 ◽  
Keyword(s):  
The Sun ◽  
Horizontal Force ◽  
Magnetic Elements ◽  
Royal Observatory ◽  
Imperial Academy ◽  
Meteorological Observations ◽  
Academy Of Sciences ◽  
Periodical Change

In a paper published in the ‘Proceedings of the Imperial Academy of Sciences of Vienna,’ vol. lxiv., Dr. Karl Hornstein has exhibited the results of a series of observations which appeared to show that the earths magnetism undergoes a periodical change in successive periods of 26 1/3 days, which might with great plausibility be referred to the rotation of the sun. It appeared to me that the deductions from the magnetic observations made at the Royal Observatory of Greenwich, and which are printed annually in the Greenwich Observations,’ or in the detached copies of ‘Results of Magnetical and Meteorological Observations made at the Royal Observatory of Greenwich, would afford good materials for testing the accuracy of this law, as applicable to a series of years. The mew results of the measured hourly ordinates of the terrestrial magnetic elements are given for every day, and it is certain that there has been no change of adjustments of the declination and horizontal-force instruments in the course of each year. For the horizontal-force instrument the temperature of the room has been maintained in a generally equable state, and in later years it has been remarkably uniform.

scholarly journals Observation of the summer solstice, 1812, at the Royal Observatory

1832 ◽  
Vol 1 ◽  
pp. 443-444
Keyword(s):  
Plumb Line ◽  
Zenith Distance ◽  
The Sun ◽  
Summer Solstice ◽  
Royal Observatory ◽  
Point Of Departure

Since a minute description of the new circular instrument, which has been lately put up at Greenwich, is intended to be given to the Society as soon as it is completed in every respect, the Astronomer Royal takes no further notice of its construction than is necessary to show by what means the results of his observations of the sun at the last solstice was obtained. In other instruments, which take their point of departure from a plumb-line or level, the zenith distance of the sun is the primary ob­ject of investigation; and the polar distance of the sun, which is the ultimate object, is obtained by adding the co-latitude of the place, which completes the entire arc.

THE WAVELENGTH DISPLACEMENTS OF SOME INFRARED LINES BETWEEN LIMB AND CENTER OF THE SUN. II

1960 ◽  
Vol 38 (6) ◽  
pp. 853-865 ◽  
Author(s):  
Luise Herzberg
Keyword(s):  
General Relativity ◽  
Light Source ◽  
Solar Limb ◽  
Relativity Theory ◽  
The Sun ◽  
General Relativity Theory ◽  
Predicted Values ◽  
Direction Opposite ◽  
Good Agreement ◽  
Neutral Metal

The differences between the wavelengths at the solar limb and at the center of the disk have been measured for lines of Fe I, Si I, and Ca II in the λ8500 Å and λ8900 Å regions of the spectrum. The values of the limb–center displacements (in km/sec) of the Fe I lines in the two wavelength regions studied are found to be the same as those obtained by M. G. Adam for neutral metal lines at λ6100 Å. The limb–center displacements of the Si I lines are similar in magnitude and in the same direction as those of Fe I. Although the data are insufficient to decide the question as to term dependence of the solar wavelength shifts of Si I, any relation to the shifts observed in a laboratory light source can be excluded. For the Ca II lines at λ8500 Å and λ8900 Å, corresponding to two different transitions, the limb–center displacements differ from each other both in magnitude and in direction. The limb–center displacements of the λ8900 Å Ca II lines are smaller than those of the Fe I lines, while those of the λ8500 Å Ca II lines are significantly larger and in direction opposite to those observed for lines of Fe I.Where possible, comparison has been made between the wavelengths observed at limb and center of the disk and the solar wavelengths predicted by General Relativity Theory. In all cases the wavelengths at the limb were found to be closer to the predicted values than the wavelengths measured at the center of the disk. While for the lines of Fe I the predicted solar wavelengths and those observed near the limb (r/R = 0.982) are in good agreement, the wavelengths close to the solar limb of the λ8500 Å Ca II lines are found to be significantly larger than those predicted by relativity theory.

XXIX. The difference of longitude between the Royal Observatory of Greenwich and Paris, determined by the observations of the transits of Mercury over the Sun in the years 1723, 1736, 1743, and 1753: By James Short, M.A. F. R. S

1763 ◽  
Vol 53 ◽  
pp. 158-169 ◽  
Keyword(s):  
The Sun ◽  
Royal Observatory ◽  
The Difference

It will, no doubt, appear surprizing, that I should attempt to determine the difference of longitude between two of the most celebrated observatories in Europe; and in which some of the greatest astronomers, that ever lived, have, for above eighty years, been constantly observing the motions of the heavenly bodies: yet it is most certain, that, to this day, we are ignorant of the said difference of longitude: the English astronomers reckoning it to be = 9' 20", and the French setting it down at 9' 10", which, they tell us, was found by M. Cassini, by observations of the eclipses of Jupiter's first satellite made by him, whilst in London in the year 1698: we are no where told, that I know of, by what observations the English astronomers have fixed this difference at 9' 20".

scholarly journals XLVII. Observations of the transit of Venus over the Sun, and the eclipse of the Sun, on June 3, 1769; made at the Royal Observatory

1768 ◽  
Vol 58 ◽  
pp. 355-365 ◽  
Keyword(s):  
The Sun ◽  
The West ◽  
Internal Contact ◽  
Royal Observatory

The weather, which had been cloudy or rainy here, with a south wind, for the greatest part of the day, began to clear up at 4 o'clock in the afternoon, the wind having returned to the west, the same quarter in which it had been the afternoon before, which was remarkably fine and serene, though it changed early in the morning preceding the transit. Towards the approach of Venus's ingress on the Sun, the sky was become again very serene, and so continued all the evening, which afforded as favourable an observation of the transit here as could well be expected, considering that the Sun was only 7° 3' high at the external, and 4° 33' at the internal contact. I observed the external contact of Venus at 7h 10' 58" apparent time, with an uncertainty seemingly not exceeding 5"; and the internal contact, by which I mean the completion of the thread of light between the circumferences of the Sun and Venus, at 7h 29' 23" apparent time, with a seeming uncertainty of only 3"; for so long was the thread of light in forming, or the Sun's light in flowing round and filling up that part of his circumference which was obscured by Venus's exterior limb.

scholarly journals Total eclipse of the Sun, 1905, August 30. Preliminary account of the observations made at Sfax, Tunisia

1906 ◽  
Vol 77 (514) ◽  
pp. 28-41
Keyword(s):  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
North Coast ◽  
The Sun ◽  
Total Eclipse ◽  
The North ◽  
Royal Observatory ◽  
Preliminary Account

An expedition to observe the total solar eclipse of August 30 having been sanctioned by the Admiralty, it was arranged, in concert with the Joint Permanent Eclipse Committee, that a party from the Royal Observatory should make observations at Sfax, a town on the north coast of Africa, about 150 miles south of Tunis. The programme of observations consisted of photographs of the corona on various scales for coronal detail and streamers, and photographs of the spectrum of the corona and chromosphere. The observers from Greenwich who took part in the expedition were Sir William Christie, Mr. Dyson, and Mr. Davidson. Professor Sampson, Mr. J. J. Atkinson, and Captain Brett, D. S. O., generously volunteered their assistance and shared the work of erecting and adjusting the instruments as well as of the observations on the day of the eclipse.

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