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 chromosphere clouds coelostat concave condensation 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 13 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 second slit 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 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 54 - 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. After passing through the two prisms it remained...
Page 124 - 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, which is further protected toward the east from the desert by the high peaks of the San Bernardino range.
Page 177 - ... among the fixed stars, which are seen by the aid of the telescope, and which exhibit a nucleus, more or less brilliant, surrounded by a cloudy brightness. " 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 223 - ... scratches. As a preliminary to polishing, the tool is placed in contact with the glass disk and pressed against it, by weights placed on the back, so that it may acquire the same curvature as the surface. After pressing for some hours, until the wax squares appear smooth and bright in all parts, the polishing may begin. This is accomplished by moving the tool over the rotating glass, by the main arm of the machine, as in the case of the grinding process. The polishing material is powdered jewelers'...
Page 177 - ... revolving the one about the other like to the double stars, whose respective motions have been already recognized. But in what manner has the solar atmosphere determined the motions of rotation and revolution of the planets and satellites? If these bodies had penetrated deeply into this atmosphere, its resistance would cause them to fall on the Sun. We may, therefore, suppose that the planets were formed at its successive limits, by the condensation of zones of vapours, which it must, while it...
Page 137 - It must be understood that the precautions mentioned are necessary only when it is desired to secure the finest possible definition of the solar image. When such precautions are used, the average photographs taken during the summer in the early morning with the Snow telescope and temporary spectroheliograph are but little inferior to the best photographs, secured on only a few days in the year, with the 40-inch Yerkes telescope and the Rumford spectroheliograph. The best photographs taken on Mount...