The Astrophysical Journal, Band 23University of Chicago Press, 1906 |
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absorption band absorption spectrum angular aperture aperture apparatus appear asteroids Astrophysical Journal atmosphere atom axis bolometer bright broaden column components corona curve determined diameter DIAPHRAGM discharge-tube disk distance double East West East eclipse effect electrons equations exposure faint film flocculi fluorite focal length fourth-type Fraunhofer lines give given grating Guelma hydrogen hydrogen lines instrument intensity investigations Lick Observatory light lines luminosity magnetic magnitude mean measures method mirror motion mounted nebula O-I O-I observations obtained Oooo optical orbit parallaxes period photosphere position pressure prisms Professor radial velocity radiation radius region reversal ring rotation Rowland screw selenium slit solar spectra spectrograph spectroheliograph spectroscope spot spectrum stars structure sun-spots Sun's taken temperature tion tube ultra-violet variable Variable Stars velocity violet Wave wave-lengths West East West Yerkes Observatory Zeeman effect ΙΟ μμ
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Seite 313 - Total Eclipse of the Sun, May 18, 1901. Reports on the Dutch Expedition to Karang Sago, Sumatra, N '. 4 : Heat Radiation of the Sun during the Eclipse", by WH JULIUS.
Seite 236 - Thus the induced current is at all times directly proportional to the total change in the number of magnetic lines of force passing through the circuit. Besides, every induced current persists so long as the new number of lines of magnetic force through the circuit is not allowed to change. In the case of any particular ring K, the value of the current is it t . • v , , t . Hence aik = - = -j— , which shows that -j~- is a constant.
Seite 6 - Snow telescope except under the conditions stated. As a matter of fact, however, very fair photographs can be obtained with the spectroheliograph at almost any time during a cool day, and in the early morning and late afternoon hours of a hot day without wind. It is only necessary to arrange the daily program of observations so that the spectroheliograph, which requires the finest definition, is used during the period when the seeing is best. Photographic work on the spectra of sun-spots follows,...
Seite 53 - Yerkes refractor. As stated in this paper, the most satisfactory form of spectroheliograph is that in which the instrument is moved as a whole, while the image of the Sun and the photographic plate are stationary. The first spectroheliograph of this type was constructed in 1893, from Mr. Hale's general design, by Toepfer, of Potsdam, and employed in some attempts to photograph the solar corona without an eclipse, from the summit of Mount Etna.
Seite 388 - Fig. 140, is in the form of a guide which is bolted to the back of the lathe. It can be set at any desired angle with the axis of the lathe, the limit usually being a taper of about three inches per foot. The guide is graduated so Fig.
Seite 200 - ... material of the electrodes, and the time of exposure are all factors which have undergone investigation. METHODS OF MEASUREMENT The methods used were two in number. The values of all the lines were first obtained by the two-slit method, and these values were then checked by obtaining the stronger lines in the second spectrum and comparing their positions with known iron lines in the first spectrum. For this last purpose the first and second spectra obtained from the left-hand slit were employed....
Seite 277 - ... whose phenomena would become predictable if we knew both the original quantity and kind of this heat; how it affects the constituents of the atmosphere on its passage earthward; how much of it reaches the soil; how, through the aid of the atmosphere, it maintains the surface temperature of this planet; and how in diminished quantity and altered kind it is returned to outer space.
Seite 65 - ... hardly one line in ten remains single and narrow when bright enough to be useful for interference work. Some lines simply broaden and reverse without other change in structure, while others double and become very complex before becoming very broad. It appears quite certain that the violet lines are much more easily affected than lines in the red, at least in arc spectra. The green mercury line X 5461 appears to be quite unique in the possession of its satellites. Of the hundreds of lines examined,...
Seite 202 - Upon the spectrum to be measured was superposed the comparison spectrum of iron, and in this spectrum fiducial lines were selected. The relative value of these lines was then obtained by subtracting the shift from their real value, previously corrected to vacuum. These relative values were then used as points of departure to determine the wave-lengths of the unknown gas spectrum. In practice the shift was 1180 Angstrom units, so that the point in the iron spectrum falling on say Xi4oo of the gas...
Seite 34 - that there is no fundamental difference between the general solar spectrum and that of the spots." If, in accordance with what appears to be his view (see the above quotation from his memoir), the spot spectrum is produced by a general increase in the intensity of the lines of the solar spectrum, no such differences in the relative intensities of the spot lines as are plainly shown in c c "fp o — 2 c '& •ft c U.