The Study of Stellar Evolution: An Account of Some Recent Methods of Astrophysical ResearchUniversity of Chicago Press, 1908 - 252 pages |
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60-inch mirror absorption advantages appear astronomical astrophysics axis bright lines calcium calcium flocculi calcium vapor camera CHAPTER chromosphere clouds coelostat concave condensation constructed dark lines diameter disk dispersion Earth eclipse electric employed exposure eye-piece faculae feet focal length gases glass graph grating heat heavens heliostat hydrogen hypothesis inches instrument intensity investigations Kenwood laboratory lens Lick Observatory light luminous ment Messier 11 meteorites method motion Mount Wilson moving nebulae nebular hypothesis object-glass objects observations obtained optical orbits phenomena photographic plate photosphere plane position prism produced prominences radiation rays red stars reflecting telescope reflector refractor regions resolving power Ritchey rotation seen shown Snow telescope solar image Solar Observatory solar prominences solar spectrum spectrograph spectroheliograph spectroscope spot spectra stellar evolution stellar spectra sun-spots Sun's sunlight surface tele temperature tion tube velocity violet Yerkes Observatory Yerkes telescope
Popular passages
Page 111 - If the Theory of making Telescopes could at length be fully brought into practice, yet there would be certain Bounds beyond which Telescopes could not perform. For the Air through which we look upon the Stars, is in a perpetual Tremor; as may be seen by the tremulous Motion of Shadows cast from high Towers, and by the twinkling of the fix'd stars. The only remedy is a most serene and quiet Air, such as may perhaps be found on the tops of the highest Mountains above the grosser Clouds.
Page 55 - The riddle of the nebulae was solved. The answer, which had come to us in the light itself, read: Not an aggregation of stars, but a luminous gas.
Page 54 - I looked Into the spectroscope. No spectrum such as I expected. A single bright line only. At first I suspected some displacement of the prism, and that I was looking at a reflection of the Illuminated slit from one of its faces. This thought was scarcely more than momentary. Then the true Interpretation flashed upon me. The light of the nebula was monochromatic, and so, unlike any other light I had as yet subjected to prismatic examination, could not be extended out to form a complete spectrum....
Page 34 - This tube, 64 feet in length, is supported at its middle point by the declination axis, which in its turn is carried by the polar axis, adjusted to accurate parallelism with the axis of the earth. By means of driving mechanism in the upper section of the iron column the whole instrument is turned about this polar axis at such a rate that it would complete one revolution in twenty-four hours. Although the moving parts weigh over 20 tons, the telescope can be directed to any part of the sky by hand,...
Page 36 - Kitchey of the observatory staff simply -places before the (isochromatic) plate a thin screen of yellow glass, which cuts out the blue rays, but allows the yellow and green rays to pass. As isochromatic plates are sensitive to yellow and green light there is no difficulty in securing an image with the rays which the object-glass unites into a perfect image.
Page 124 - ... west, beyond the saddle leading to Mount Harvard, the ridge of Mount Wilson forms the upper extremity of Eaton Canon, which leads directly to the San Gabriel Valley. East and north of Mount Wilson lies the deep canon through which flows the west fork of the San Gabriel River, and beyond this rises a constant succession of mountains, most of them higher than Mount Wilson, which extend in a broken mass to the Mojave Desert. The Sierra Madre range forms the northern boundary of the San Gabriel Valley,...
Page 177 - This anterior state was itself preceded by other states, in which the nebulous matter was more and more diffuse, the nucleus being less and less luminous. We arrive," Laplace says, " in this manner, at a nebulosity so diffuse, that its existence could scarcely be suspected.
Page 3 - We are now in a position to regard the study of evolution as that of a single great problem, beginning with the origin of the stars in the nebulae and culminating in those difficult and complex sciences that endeavor to account, not merely for the phenomena of life, but for the laws which control a society composed of human beings.
Page 86 - The calcium regions above referred to are usually associated with the faculae, but they lie above them, and they give no trace of their existence on ordinary photographs, like the one in Fig. 4, or to the eye when observing the sun through a telescope. The results of the first experiments, which were made at the beginning of 1892, were such as to justify fully the expectations that had been entertained. It was at once found possible to record the forms, not only of the brilliant clouds of calcium...