Contributions from the Mount Wilson Observatory, Band 1The Institution, 1908 The majority of the contributions are reprinted from the Astrophysical journal. |
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absorption Ångströms appear Astrophysical Journal atmosphere bands bright calcium calcium flocculi carbon Carnegie Institution chromosphere coelostat components concave mirror Contributions dark diameter disk doublets effect electric elements enhanced lines exposure faculae feet flutings focal length furnace HALE Hasselberg gives heliograph hydrogen flocculi hydrogen lines inches instrument investigation iron laboratory latitude limb Littrow magnetic field means measured motion Mount Wilson Solar narrow Nicol O-I O-I observations obtained Oooo phenomena photographs photosphere pier plates position prisms region rotation Rowland Rowland's intensity second mirror slit Snow telescope solar image solar spectrum Spark line spectra spectrograph spectroheliograph spectroscope spot lines spot spectrum stars stellar strengthened sun-spots sun's TABLE I-Continued temperature tion titanium tower telescope tube vanadium vapor velocity vertical violet wave-lengths weak arc weakened Widened widened lines Wilson Solar Observatory Yerkes Observatory Zeeman effect ΙΟ
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Seite 84 - 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.
Seite 322 - Double lines, which look like reversals, have recently been photographed in spot spectra with the 30-foot spectrograph of the tower telescope, confirming the visual observations of Young and Mitchell. It should be determined whether the components of these double lines are circularly polarized in opposite directions, or, if not, whether other less obvious indications of a magnetic field are present.
Seite 213 - Of these the most noteworthy is the spectroscopic appearance of a spot and its penumbra. As is well known, such a spectrum exhibits a very strong general absorption, with a very slightly modified elective absorption. A few faint lines appear in the spot spectrum which are not otherwise seen ; and a few faint lines of the ordinary spectrum are strengthened. A careful examination has persuaded me that the spectrum of a spot differs from that of the unbroken photosphere, just as the spectrum of the...
Seite 9 - Mount Harvard by a deep canon, the walls of which are very precipitous. Farther to the 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...
Seite 104 - 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 133 - In considering the characteristic features of the spectra of sun-spots, three points especially attract attention : — 1. The fact that certain lines in the spectrum of a given element are strengthened, while others are weakened ; the remainder of the lines being unaffected. 2. The inclusion of all the strengthened lines within the visible spectrum, none of them occurring in the ultra-violet, and their predominance in the red, yellow, and green. 3. The relatively great intensity of the continuous...
Seite 322 - ... confirming the visual observations of Young and Mitchell. It should be determined whether the components of these double lines are circularly polarized in opposite directions, or, if not, whether other less obvious indications of a magnetic field are present. I shall attempt the necessary observations as soon as a suitable spot appears on the sun.
Seite 309 - This is so definite in form and so unmistakable in character as to satisfy the hopes aroused by the earlier photographs. It seems evident, on mere inspection of these photographs, that sun-spots are centers of attraction, drawing toward them the hydrogen of the solar atmosphere. Moreover, the clearly defined whirls point to the existence of cyclonic storms or vortices.
Seite 321 - The forked connection to the two spots has disappeared and a strong, dark flocculus has developed at the southern extremity of the radial line, mainly on its eastern side. With the stereocomparator the main body of the large flocculus is found to resemble its former appearance in some particulars, but the distribution of intensities is very different and many changes in outline have occurred. In the photograph of June 5th, at 7h O5m AM (No.
Seite 310 - No. 4175, but exhibit some marked changes. An eruption which appears on the former plate southeast of the spot continues, but is changed in form and less brilliant than before. A strong eruption, of peculiar form, appears southwest of the spot, and bright hydrogen to the northeast. Strong dark flocculi have also developed at many points around the spot. The eastern end of the long dark flocculus is still changing, and a projection appears west of its center (see Plate X).