Astronomical Register: A Medium of Communication for Amateur Observers and All Others Interested in the Science of Astronomy, Band 19

Cover
J. D. Potter., 1882
 

Andere Ausgaben - Alle anzeigen

Häufige Begriffe und Wortgruppen

Beliebte Passagen

Seite 253 - Cephei may be noted. Fifthly, we have a class of stars which during the greater part of the time remain unchanged in brightness, but at regular intervals lose in the course of a few hours a large part of their light, and regain it with equal rapidity. These changes appear to be repeated with the greatest regularity, so that the interval can be computed in some cases within a fraction of a second. Algol, or /3 Persei, is the most striking example of this class to which S Cancri and d Libra also belong.
Seite 162 - I obtained, with one hour's exposure, a photograph on a gelatine plate of the more refrangible part of the spectrum of the comet which is now visible. This photograph shows a pair of bright lines a little way beyond H in the ultra-violet region, which appear to belong to the spectrum of carbon (in some form) which I observed in the visible region of the spectra of telescopic comets in 1866 and 1868. There is also in the photograph a continuous spectrum in which the Fraunhofer lines can be seen. These...
Seite 197 - it was not the person who locked up his invention in his scrutoire that ought to profit by a patent for such invention, but he who brought it forth for the benefit of the public.
Seite 195 - tis so corrected, that it emergeth in Lines parallel to those in which it was incident, continues ever after to be white. But if the emergent Rays be inclined to the incident, the Whiteness of the emerging Light will by degrees in passing on from the Place of Emergence, become tinged in its Edges with Colours. This I try'd by refracting Light with Prisms of Glass placed within a Prismatick Vessel of Water. Now those Colours argue a diverging and separation of the heterogeneous Rays from one another...
Seite 218 - After an exposure of 83 minutes, a strong picture of the spectrum of the nucleus, coma, and part of the tail was obtained, but the banded spectrum was overpowered by the continuous spectrum. I then applied the two-prism spectroscope used for stellar spectrum photography, anticipating that although the diminution of light would be serious after passing through the slit, two prisms, and two object-glasses, yet the advantage of being able to have a juxtaposed comparison spectrum would make the attempt...
Seite 197 - Hall, in Essex, who, about 1729, as appears by his papers, considering the different humours of the eye, imagined they were placed so as to correct the different refrangibility of light. He then conceived, that if he could find substances having such properties as he supposed these humours might possess, he should be enabled to construct an object-glass that would shew objects colourless.
Seite 202 - Arcturus for fifteen minutes. After development, the plate presented a very distinct spectrum of the comet, together with the spectrum of the star, which I have already described in the paper referred to above. The spectrum of the comet consists of a pair of bright lines in the ultra-violet region, and a continuous spectrum which can be traced from about F to some distance beyond H. The bright...
Seite 86 - Years more, he should be able to supply the Governor's Gardens with Sunshine at a reasonable Rate...
Seite 203 - Lockyer regards the tw o groups in the photograph, and the groups in the visible spectrum, to be due to the vapour of carbon at different heat-levels (Proc. Roy. Soc., voL xxx. p. 461). It is of importance to mention the strong intensity in the photograph of the lines 3883 and 3870, as compared with the continuous spectrum, and the faint bright group beginning at 4230. At this part of the spectrum, therefore, the light emitted by the cometary matter exceeded by many times the reflected solar light....
Seite 196 - Now in these new telescopes the images of objects are formed by the difference between two contrary refractions, the object glass being a compound of two or more glasses put close together, whereof one is concave and the other convex. The excess of refraction by which the image is formed is in the convex glass, which is made of a medium or substance in which the difference of refrangibility is not so great as in the substance which the concave is made of, therefore their refractions being proportional...

Bibliografische Informationen