scholarly journals III. On the corrections of Bouvard’s elements of Jupiter and Saturn (Paris, 1821)

1869 ◽  
Vol 17 ◽  
pp. 344-346
Keyword(s):  
Mean Error ◽  
The Earth ◽  
Royal Observatory ◽  
The Mean ◽  
The Difference ◽  
Nautical Almanac

The Tables of Jupiter and Saturn which have been used for some years past in the computations of the ‘Berliner Jahrbuch’ and ‘Nautical Almanac,’ differ more from observation than is consistent with the present requirements of astronomy; and, moreover, abundant means for the correction of Bouvard’s ‘Elements’ exist in the publication of the Greenwich Planetary Observations, 1750-1835, and the annual volumes issued from the Royal Observatory since 1836. The present work, which has been undertaken for this purpose, is based exclusively on the Greenwich Observations, 1750-1865. Each mean group of observations in the Greenwich Planetary Reductions &c. gives the mean error of the planet’s tabular geocentric place, with its equivalent in terms of the heliocentric errors of the earth and planet; but in the present investigation the places of Carlini’s Solar Tables, which have been used throughout the whole period (with the exception of 1864 and 1865), have been accepted without alteration; for Jupiter and Saturn the factors of the earth’s heliocentric errors are so small, that the difference of Carlini’s Solar Tables from the recent investigations of Leverrier rnay be neglected.

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.

On an inequality of long period in the motions of the Earth and Venus

1837 ◽  
Vol 3 ◽  
pp. 77-78
Keyword(s):  
Principal Term ◽  
The Sun ◽  
Method Of Calculation ◽  
The Third ◽  
Long Period ◽  
Mean Motion ◽  
The Earth ◽  
The Mean ◽  
The Difference

The author had pointed out, in a paper published in the Philosophical Transactions for 1828, on the corrections of the elements of Delambre’s Solar Tables, that the comparison of the corrections of the epochs of the sun and the sun’s perigee, given by the late observations, with the corrections given by the observations of the last century, appears to indicate the existence of some inequality not included in the arguments of those tables. As it was necessary, therefore, to seek for some inequality of long period, he commenced an examination of the mean motions of the planets, with the view of discovering one whose ratio to the mean motion of the earth could be expressed very nearly by a proportion of which the terms are small. The appearances of Venus are found to recur in very nearly the same order every eight years; some multiple, therefore, of the periodic time of Venus is nearly equal to eight years. It is easily seen that this multiple must be thirteen; and consequently eight times the mean motion of Venus is nearly equal to thirteen times the mean motion of the earth. The difference is about one 240th of the mean annual motion of the earth; and it implies the existence of an inequality of which the period is about 240 years. No term has yet been calculated whose period is so long with respect to the periodic time of the planets disturbed. The value of the principal term, calculated from the theory, was given by the author in a postscript to the paper above referred to. In the present memoir he gives an account of the method of calculation, and includes also other terms which are necessarily connected with the principal inequality. The first part treats of the perturbation of the earth’s longitude and radius victor; the second of the perturbation of the earth in latitude; and the third of the perturbations of Venus depending upon the same arguments.

scholarly journals III. Account of the observations and computations made for the purpose of ascertaining the amount of the deflection of the plumb-line at Arthur’s seat, and the mean specific gravity of the Earth; with an account of the observed and computed amount of the local attraction at Arthur’s seat and at the Royal Observatory at Edinburgh

1857 ◽  
Vol 8 ◽  
pp. 45-47
Keyword(s):  
Plumb Line ◽  
Great Pleasure ◽  
Ordnance Survey ◽  
The Public ◽  
The United Kingdom ◽  
The Earth ◽  
Royal Observatory ◽  
The Press ◽  
The Mean

Col. James begins by observing, that as the Royal Society has, from the very commencement of the Ordnance Survey of the United Kingdom, taken a deep interest in its progress, he has great pleasure in announcing to the Society that all the computations connected with the Primary Triangulation, the measurement of the Arcs of Meridians and the determination of the figure and dimensions of the earth are now completed, and that the account of all the operations and calculations which have been undertaken and executed is now in the press, and will shortly be in the hands of the public. In the progress of these operations it has been found, on determining the most probable spheroid from all the astronomical and geodetic amplitudes in Great Britain, that the plumb-line is considerably deflected at several of the principal Trigonometrical Stations, and at almost every station the cause of the deflection is apparent in the configuration of the surrounding country.

Reply to Discussion by J. R. Hearst and R. C. Carlson

Geophysics ◽  
1979 ◽  
Vol 44 (8) ◽  
pp. 1464-1464
Author(s):  
J. R. Hearst ◽  
R. C. Carlson
Keyword(s):  
Outer Radius ◽  
The Other ◽  
Gradient Term ◽  
The Earth ◽  
Other Hand ◽  
Free Air ◽  
Inner Radius ◽  
The Mean ◽  
The Difference

Our equations (3) and (4) are correct. They represent the difference between the attraction of the shell viewed from [Formula: see text], the outer radius of the shell, and [Formula: see text], its inner radius. (The attraction of the shell viewed from [Formula: see text] is zero.) On the other hand, equations (5) and (6) of Fahlquist and Carlson represent the difference in attraction of the entire earth from the same viewpoints and thus, as they say, include a free‐air gradient term. However, their equation (5) would be correct only if the mean density of the earth were equal to that of the shell, and the free‐air gradient obtained by their equation (10) is correct only under these circumstances.

VIII. On the corrections to be applied to the monthly means of meteorological observations taken at any hour, to convert them into mean monthly values

1848 ◽  
Vol 138 ◽  
pp. 125-139 ◽  
Keyword(s):  
Monthly Means ◽  
Mean Values ◽  
Short Intervals ◽  
Perfect Knowledge ◽  
Royal Observatory ◽  
The Mean ◽  
The Difference ◽  
Meteorological Observations ◽  
Essential Service

One of the most useful results of observations made at short intervals during the day and night, and continued for several years, is the knowledge we thus obtain of the diurnal ranges of the different subjects of investigation, and consequently the difference between the mean values of each element, as deduced from observations at one or more hours daily, and the true mean for the period over which the observations are spread. At the Royal Observatory at Greenwich magnetical and meteorological observations have been taken since the year 1840, as is familiar to the Fellows of this Society. These have been published to the end of the year 1845. The whole of these observations have been made under my immediate superintendence, under the direction of the Astronomer Royal, and I believe that no observations have been made and reduced with greater care or regularity. As the person entrusted with the superintendence of these operations, I have a more perfect knowledge of them than any other person can have; I feel it therefore a duty to communicate their results from time to time, when the doing so promises to be of essential service in promoting the advancement of the subjects of investigation.

scholarly journals Observations made with the invariable pendulum (No. 4. Jones), at the royal observatory, cape of good hope, for the purpose of determining the compression of the earth

1833 ◽  
Vol 2 ◽  
pp. 396-397
Keyword(s):  
Considerable Time ◽  
Cape Of Good Hope ◽  
The Earth ◽  
Direct Measurements ◽  
Royal Observatory ◽  
Figure Of The Earth ◽  
Geographical Position ◽  
Series Of Experiments ◽  
Independent Series ◽  
The Difference

Of the two methods employed for determining the figure of the earth, namely, the direct measurements of arcs of the meridian, or of ascertaining the variations in the length of the seconds pendulum in different places, the author remarks that the former is attended with the collateral benefit of fixing the geographical position of certain stations in the country surveyed; but the latter possesses the advantage of enabling the observer to concentrate, under his own immediate eye, the results of his inquiries. The Observatory at the Cape of Good Hope having been furnished by the Lords Commissioners of the Admiralty with the invariable pendulum of Jones, which had for several years been strictly examined by Capt. Sabine, the author was anxious to begin a series of experiments with it; and as it was not likely that the observatory would be completed for a considerable time, he caused a strong brick pier to be built in an adjoining outhouse for the support of a transit instrument, the same which he had used in forming his catalogue of southern stars. He gives a detailed account of his mode of fitting up the clock, and other parts of the apparatus necessary for the pendulum experiments. He was ably assisted by Capt. Ronald and Lieut. Johnson, who took an active part in all the observations. He remarks, that the near agreement of the three independent series of observations, made by himself and these two gentlemen, and which accompany the paper, is no small argument in favour of their accuracy. The difference in the number of vibrations of the seconds pendulum at the Cape, from that in London, in a mean solar day, he finds to be 67·12, from which it results that the compression of the earth is 1/288.5. The author is of opinion that the invariable pendulum ought to be a standard instrument in every observatory; that it should be swung at all seasons of the year, and occasionally transferred to various fixed observatories in both hemispheres, and returned again to its original station, where it should undergo a renewed and rigid examination before it is sent round on a fresh circuit of these stations.

A Device to Determine Position Rapidly Without Calculation

1956 ◽  
Vol 9 (1) ◽  
pp. 11-16
Author(s):  
Leo Randić
Keyword(s):  
Sidereal Time ◽  
Outer Circle ◽  
The Earth ◽  
Geographical Latitude ◽  
The Difference ◽  
Celestial Sphere ◽  
The Right ◽  
Right Ascension ◽  
Nautical Almanac

The problem of the determination of the observer's position on the Earth can be most easily solved in terms of the equatorial coordinates of the observer's zenith. From Fig. 1, in which the inner circle represents the Earth and the outer circle the celestial sphere, it can be seen that the zenithal point on the celestial sphere is its intersection with the prolongation of the radius to the observer's position. The geographical latitude of the observer is equal to the declination of the observer's zenith, and the geographical longitude is equal to the difference between Greenwich sidereal time (G.S.T.) and the right ascension of the observer's zenith. We can obtain G.S.T. by interpolation from a nautical almanac or directly from a separate watch or clock set to keep sidereal time.

scholarly journals Experiments to determine the difference in the number of vibrations made by an invariable pendulum in the Royal Observatories of Greenwich and Altona

1833 ◽  
Vol 2 ◽  
pp. 403-403
Keyword(s):  
Royal Observatory ◽  
The Mean ◽  
The Difference

The invariable pendulum, No. 12, with which the experiments recorded in this paper were made, was vibrated in the Royal Observatory at Greenwich in July 1828; in the Royal Observatory at Altona in September and October of the same year; and again at the Royal Observatory at Greenwich in August 1829. The mean of the results obtained at Greenwich in July 1828 and in August 1829, give the rate of this pendulum at Greenwich to be compared with its rate obtained at Altona. The details of all these series of observations are given in a tabulated form.

scholarly journals Asymmetry between galaxies with different spin patterns: A comparison between COSMOS, SDSS, and Pan-STARRS

2020 ◽  
Vol 29 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Lior Shamir
Keyword(s):  
Spiral Galaxy ◽  
Spiral Galaxies ◽  
Automatic Process ◽  
Human Intervention ◽  
Rotation Direction ◽  
The Earth ◽  
Fully Automatic ◽  
The Mean ◽  
The Difference ◽  
Different Parts

AbstractPrevious observations of a large number of galaxies show differences between the photometry of spiral galaxies with clockwise spin patterns and spiral galaxies with counterclockwise spin patterns. In this study the mean magnitude of a large number of clockwise galaxies is compared to the mean magnitude of a large number of counterclockwise galaxies. The observed difference between clockwise and counterclockwise spiral galaxies imaged by the space-based COSMOS survey is compared to the differences between clockwise and counterclockwise galaxies imaged by the Earth-based SDSS and Pan-STARRS around the same field. The annotation of clockwise and counterclockwise galaxies is a fully automatic process that does not involve human intervention, and in all experiments both clockwise and counterclockwise galaxies are separated from the same fields. The comparison shows that the same asymmetry was identified by all three telescopes, providing strong evidence that the rotation direction of a spiral galaxy is linked to its luminosity as measured from Earth. Analysis of the luminosity difference using a large number of galaxies from different parts of the sky shows that the difference between clockwise and counterclockwise galaxies changes with the direction of observation, and oriented around an axis.

scholarly journals Remarks on the probabilities of error in physical observations, and on the density of the Earth, considered, especially with regard to the reduction of experiments on the pendulum. In a letter to Capt. Henry Kater, F. R. S. By Thomas Young, M. D. For. Sec. R. S

1833 ◽  
Vol 2 ◽  
pp. 106-108
Keyword(s):  
Joint Effect ◽  
Square Root ◽  
Black And White ◽  
Mean Error ◽  
The Earth ◽  
Natural Tendency ◽  
The Mean

In the first section of this letter, Dr. Young proceeds to examine in what manner the apparent constancy of many general results, subject to numerous causes of diversity, may be best explained; and shows that the combination of many independent causes of error, each liable to incessant fluctuation, has a natural tendency, dependent on their multiplicity and independence, to diminish the aggregate variation of their joint effect; a position illustrated by the simple case of supposing an equal large number of black and white balls to be thrown into a box, and 100 of them to be drawn out at once or in succession; when it is demonstrated that there is 1 chance in 12 1/2; that exactly 50 of each kind will be drawn, and an even chance that there will not be more than 53 of either; and that it is barely possible that 100 black, or 100 white, should be drawn in succession. From calculations contained in this paper, Dr. Young infers that the original conditions of the probability of different errors do not considerably modify the conclusions respecting the accuracy of the mean result, because their effect is comprehended in the magnitude of the mean error from which these conclusions are deduced. The author also shows that the error of the mean, on account of this limitation is never likely to be greater than six sevenths of the mean of all the errors divided by the square root of the number of observations.

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