The Astrophysical Journal, Volume 6University of Chicago Press, 1897 "Letters to the Editor" issued as Part 2 and separately paged from v. 148, 1967. Beginning in 2009, the Letters published only online. |
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Common terms and phrases
AA observed AA reduced angle aperture apparatus astronomical ASTROPHYSICAL JOURNAL Average bright line calcium celestial chromosphere corresponding curve d₁ d₂ dark line density determined disk Displacem't distance ecliptic elements equator faculæ field followed by AA formula forty-inch given heliographic Hẞ hydrogen inches increase instrument investigations July Kayser latitude length lens Lick Observatory light limb longitude means measured metallic method micrometer motion nebula objective observed and Pressure obtained Orion Nebula paper photographs photosphere plane plate polar pole position present Pressure in atmospheres prism Professor radiation red end region resolving power right ascension rutile shifts slit solar spectrum spectra spectral lines spectrogram spectroscope spots stellar Sun-spot Sun's TABLE temperature tion triplets values vanadium vapor variable stars velocity wave Wave-length tenth-meters Intensity width Williams Bay Yerkes Observatory Yerkes telescope
Popular passages
Page 288 - States cannot be constructed without astronomical observations at numerous points scattered over the whole country, aided by data which great observatories have been accumulating for more than a century, and must continue to accumulate in the future. But neither the measurement of the earth, the making of maps, nor the aid of the navigator is the main object which the astronomers of to-day have in view. If they do not quite share the sentiment of that eminent mathematician, who is said to have thanked...
Page 298 - ... for scientific and public purposes. Each of the leading nations of western Europe issues such a publication. When the preparation and publication of the American ephemeris was decided upon the office was first established in Cambridge, the seat of Harvard University, because there could most readily be secured the technical knowledge of mathematics and theoretical astronomy necessary for the work. A field of activity was thus opened, of which a number of able young men who have since earned distinction...
Page 271 - It is the universal law that whatever pursuit, whatever doctrine becomes fashionable shall lose a portion of that dignity which it had possessed while it was confined to a small but earnest minority, and was loved for its own sake alone.
Page 78 - ... to find out by experiments in the laboratory, under -what conditions the lines of calcium other than the lines H and K, and in particular the strong blue line at 4226'9, were so greatly enfeebled relatively to H and K, that they became quite insignificant, or even disappeared altogether from the spectrum, leaving the very simple spectrum of the two lines H and K, or nearly so. Professor Lockyer states that : — " Some of the substances which have been investigated, including iron, calcium, and...
Page 77 - Young from a few weeks' work at Sherman on the spectra of the chromosphere and of the prominences, was able to point out that " the selection of lines seems most capricious; one is taken and another is left, though belonging to the same element, of equal intensity, and close beside the first.
Page 322 - Another way of looking at the problem is perhaps possible. May it be that the effect of the great mass on surface density, together with the working of Lane's law, by which the temperature of a condensing gaseous mass so long as it is subject to the laws of a purely gaseous body will continue to rise, will favor in such stars the coming in of a solar type of spectrum at a somewhat relatively earlier time?
Page 300 - ... years ago at what point in the United States a great school of theoretical and practical astronomy,, aided by an establishment for the exploration of the heavens, was likely to be established by the munificence of private citizens, he would have been wiser than most foreigners had he guessed Chicago. Had this place been suggested to him, I fear he would Have replied that were it possible to utilize celestial knowledge in acquiring earthly wealth, here would be the most promising seat for such...
Page 294 - Happily, no such contest has been fought over the astronomical as over the surgical discovery, the fact being that all who were engaged in the application of the new method were more anxious to perfect it than they were to get credit for themselves. We know that Saxton, of the Coast Survey; Mitchell and Locke, of Cincinnati; Bond, at Cambridge, as well as Walker, and other astronomers at the Naval Observatory, all worked at the apparatus; that Maury seconded their efforts with untiring zeal; that...
Page 293 - Washington, and supplied with a transit instrument for observing moon culminations, in conjunction with Captain Wilkes, who was then setting out on his exploring expedition to the Southern Hemisphere. The date of these observatories was practically the same as that on which a charter for the city of Chicago was obtained from the legislature. With their establishment the population of your city had increased to 703. The next decade, 1840 to 1850, was that in which our practical astronomy seriously...
Page 418 - ... lines. Their relatively greater strength in the star spectrum gives to some well-known solar groups (notably the b group) quite an unfamiliar aspect. In a Herculis only a comparatively few of the strong metallic lines remain, while the bands are deep, and beautifully distinct. It is impossible to avoid the conclusion that the edges of the zones bordering on the dark bands are bright — much brighter, that is, than the average continuous spectrum...