| 单词 | annual parallax |
| 例句 | The annual parallax of a heavenly body is the angle subtended at that body by the radius of the Earth’s orbit. The Astronomy of Milton's 'Paradise Lost' It should be explained that what is called the "annual parallax" of a star is only half its apparent displacement. A Popular History of Astronomy During the Nineteenth Century Fourth Edition Half of this major axis, or, what comes to the same thing, the angle which the radius of the earth's orbit subtends as seen from the star, is called the star's "annual parallax." The Story of the Heavens The annual parallax of a star is the angle under which one would see the radius, or half-diameter, of the terrestrial orbit from it. Astronomy for Amateurs The seventh and eighth columns give the annual parallax and the corresponding distance expressed in siriometers. Lectures on Stellar Statistics It is improbable, however, that even these nearer stars are practicable subjects for the direct determination of annual parallax. Scientific American Supplement, No. 623, December 10, 1887 With their annual parallax, however, the case was very different. A Popular History of Astronomy During the Nineteenth Century Fourth Edition We have in a previous chapter discussed the important question of the annual parallax of stars, and we have shown how, in virtue of annual parallax, each star describes an ellipse. The Story of the Heavens William Herschel began his observations of double stars in the hope of discovering an annual parallax of the stars. History of Astronomy We have already pointed out that distances greater than 4 sir., when computed from annual parallaxes, must generally be considered as rather uncertain. Lectures on Stellar Statistics Hence, of all the stars in the Pleiades these are the most likely to have a measurable annual parallax. Scientific American Supplement, No. 623, December 10, 1887 It should also be noticed that the movements of a star produced by annual parallax are much smaller than those due to aberration. The Story of the Heavens If the movement arise from annual parallax, it is easy to see where the place of the star will be for any position of the earth. The Story of the Heavens For these reasons Bradley had set up this instrument at Kew, to attempt the proof of the earth’s motion by observing the annual parallax of stars. History of Astronomy In §22 I have paid attention to the now available catalogues of stars with known annual parallax. Lectures on Stellar Statistics So small a parallax value is of little reliability when it is directly computed from annual parallax observations, but is more trustworthy when derived with the spectroscopic method of Adams. Lectures on Stellar Statistics In order to obtain available annual parallaxes of a star it is usually necessary for the star to be nearer to us than 5 siriometers, corresponding to a parallax greater than 0″.04. Lectures on Stellar Statistics It can further be demonstrated that these ellipses are really circles parallel to the ecliptic; so that we might hastily assume that annual parallax was the cause of the phenomenon discovered by Bradley. The Story of the Heavens The absence of annual parallax further involves an incredible distance between the outermost planet and the fixed stars. History of Astronomy The annual parallax can only be determined for near stars, nearer than, say, 5 siriometers. Lectures on Stellar Statistics Here we have only to do with near stars for which the annual parallax is well determined. Lectures on Stellar Statistics |
| 随便看 |
英语例句辞典收录了117811条英语例句在线翻译词条，基本涵盖了全部常用单词及词组的例句翻译及用法，是英语学习的有利工具。