scholarly journals Remarks on a correction of the solar tables required by Mr. South’s observations

1833 ◽  
Vol 2 ◽  
pp. 305-305
Keyword(s):  
The Sun ◽  
Peculiar Form ◽  
The Mean ◽  
Right Ascension ◽  
Nautical Almanac

The discordancies observed by Mr. South between the sun’s right ascension, as deduced from observation, and those given in the Nautical Almanac, follow a law so simple as not to allow of their being regarded as errors of observation, or arising from any casual cause, but justify us in attributing them to imperfections in the solar tables, with the exception of three days, in which there seems to be some ground to suspect error of computation. A single inspection of these discrepancies, Mr. Airy observes, suffices to show that they arise almost entirely from an error in the epoch, and an error in the place of the perigee. From the peculiar form of the tables in Vince’s Astronomy, which give great facility to the introduction of an error in the excentricity, he was induced at first to suspect that one might exist; but on calculation found the error in the equation of the centre so small as to be entirely insensible. He then proceeds to detail the process by which, from Mr. South’s observations, he has deduced the amount of the several errors, which consist in regarding the epoch, the mean anomaly, and the equation of the centre, as erroneous by three very small unknown quantities, and forming as many equations of condition for determining them as there are observations. These combined and resolved, so as to give the most probable result, lead to the conclusions, first, that the correction of the equation of the centre is evanescent; secondly, that the epochs of the sun must all be increased by 9", and the epochs of the perigee each by 1' 48".

Astronomical observations

1833 ◽  
Vol 2 ◽  
pp. 135-135
Keyword(s):  
Direct Method ◽  
The Sun ◽  
Vernal Equinox ◽  
Astronomical Observations ◽  
The World ◽  
The Mean ◽  
The Right ◽  
Right Ascension ◽  
Nautical Almanac

In the present improved state of astronomical observations, it is material to possess the readiest and most accurate means of finding the apparent time. The right ascension of certain fixed stars having been precisely obtained relatively with each other, and with the equinoctial points during the course of many years, affords the direct method of ascertaining the right ascension of the mid-heaven: hence the convenience of having the corrections of these stars in the form of tables, that the same may be taken out at one view with the arguments of the sun’s longitude, and of the moon’s node. For this purpose the mean diurnal motion is adapted to the longitude of the sun, as found in the Nautical Almanac, at the time the star passes the meridian. The mean epoch is reduced to the vernal equinox less four seconds, in order to render the corrections additive; which, being an universal period, the same applies to all parts of the world. To these tables Mr. Groombridge has subjoined some observations of the planets at and near the oppositions; also of the solstices of the last two years, and of the comet of 1819.

The New Abridged Nautical Almanac

1951 ◽  
Vol 4 (04) ◽  
pp. 377-385
Keyword(s):  
Present Form ◽  
Transitional Period ◽  
The Sun ◽  
American Spanish ◽  
Detailed Work ◽  
Right Ascension ◽  
Nautical Almanac

TheAbridged Nautical Almanacin its revised form, for the year 1952, has now appeared. In place of right ascension and the familiar quantitiesEandRwhich were adopted in 1929, it tabulates Greenwich hour angle in arc for the Sun, Moon, planets and Aries, and sidereal hour angle (or versed ascension) for the stars.Greenwich hourangle has been used in air almanacs for a number of years, and several surface almanacs have tabulated it as an alternative to right ascension; it is only recently, however, that it has been given exclusively in surface almanacs. Among the surface almanacs which tabulate G.H.A. at present are the American, Spanish, Argentine, Brazilian and Yugoslav.The redesign of theAbridged Nautical Almanachas been under consideration for many years, but the change was delayed first by the war, and then by the desire to avoid a transitional period during which the new G.H.A. andEandRwere given together; it was also decided to give as much notice of the proposed changes to users as possible. The design in substantially its present form was in fact accomplished in 1947, though the arrangement of the daily pages and much detailed work was carried out later.

scholarly journals Graphical Methods of Finding the Sun's Azimuth and Elevation

1963 ◽  
Vol 16 (3) ◽  
pp. 369-374
Author(s):  
D. H. Shinn
Keyword(s):  
Radiation Pattern ◽  
Vertical Plane ◽  
Graphical Form ◽  
Graphical Methods ◽  
The Sun ◽  
Simple Method ◽  
The Mean ◽  
Nautical Almanac ◽  
Local Noon

Like Mr. R. S. Blicq (Journal 15,456) we have also been concerned in supplying details of the Sun's position to engineers on radar sites who use radiation from the Sun for, at present, two purposes:(a) Measuring or checking the radiation pattern of the aerial in the vertical plane.(b) Lining up the aerial in azimuth or elevation.For these purposes the required accuracy of computation is usually about ±0°·1 in azimuth and elevation. Greater accuracy is never required, but less accuracy is sometimes adequate, up to ±1°.We have found that graphical methods appeal most to engineers, and that even when a full table of values is supplied to them they prefer to display this information in graphical form. We have accordingly evolved a simple method of constructing graphs of elevation against time, and azimuth against time.In order to achieve the required accuracy of ±0°·1 in elevation we have constructed a graticule of size 21 in. × 40 in. A skeleton version of this is shown in Fig. 1. The engineer has to know his latitude, and to find, from the Nautical Almanac or other source, the time of local noon (i.e. when the Sun is due south) and the mean declination, δ, of the Sun during the period of observation, which usually lasts up to three hours.

2. Solar Eclipse, 31st December 1880

1882 ◽  
Vol 11 ◽  
pp. 18-19
Author(s):  
E. Sang
Keyword(s):  
Solar Eclipse ◽  
The Sun ◽  
Actual Observation ◽  
Lunar Ephemeris ◽  
The Times ◽  
The Right ◽  
Right Ascension ◽  
Nautical Almanac

The elements for the compution of eclipses are given in the “Nautical Almanac” with precision sufficient for all ordinary purposes; but, when we wish to compare the lunar ephemeris with actual observation for the purpose of verifying or of improving our data, we must go somewhat more minutely into the investigation.Thus, in the List of Elements, p. 403, the changes in the right-ascension and declination of the sun and moon are supposed to be proportional to the times, while the moon's geocentric semidiameter, as well as the horizontal parallax, is supposed to be constant during the eclipse. In this way some exceedingly small errors are introduced into the calculation.

scholarly journals Comparison Of The Effect Of Various Solar System Ephemerides On Equator And Equinox Solutions From Six-inch Transit Circle Observations Of The Sun

1988 ◽  
Vol 133 ◽  
pp. 501-504
Author(s):  
Zhen-Guo Yao ◽  
Clayton Smith
Keyword(s):  
Solar System ◽  
Zero Point ◽  
The Sun ◽  
Proper Motions ◽  
Orbital Parameters ◽  
The Mean ◽  
The Right ◽  
Right Ascension

Using observations of the sun made with the Washington six-inch transit circle from 1911 to 1971, equator and equinox corrections based on Newcomb's, DE102, and DE200 ephemerides are given for each of six catalogs of results of observations made during that period. Each of these catalogs was observed and discussed fundamentally, that is, in such a way as to decouple the system of the catalog positions from dependence on previously given systems of catalog positions and proper motions.Variations of the solutions for the equator and equinox corrections and of earth orbital parameters including corrections to the ephemeris mean longitude of the sun, the mean obliquity of the ecliptic, the mean longitude of perihelion, and the mean eccentricity of the earth's orbit are discussed for solutions based on the independent catalog systems and on the catalog systems referred to the FK4 and to an improved FK4 in which an epoch dependent correction to the right ascension zero point has been applied.

Fundamental observations made at Breslau in 1922-1925

1978 ◽  
Vol 48 ◽  
pp. 433-435
Author(s):  
F. Schmeidler
Keyword(s):  
The Sun ◽  
Vertical Circle ◽  
Right Ascension

Meridian observations of fundamental stars were made at Breslau Observatory in 1922 to 1925. The observations in right ascension were made by W.Rabe with the 6-inch transit instrument, whereas the declinations were observed by A.Wilkens with the vertical circle. In both coordinates, observations of the Sun were also made.

scholarly journals The mean magnetic field of the Sun: Observations at Stanford

Solar Physics ◽  
1977 ◽  
Vol 54 (2) ◽  
pp. 353-361 ◽  
Author(s):  
Philip H. Scherrer ◽  
John M. Wilcox ◽  
Leif Svalgaard ◽  
Thomas L. Duvall ◽  
Phil H. Dittmer ◽  
...  
Keyword(s):  
Magnetic Field ◽  
The Sun ◽  
The Mean
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