Page:Popular Science Monthly Volume 11.djvu/73

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THE NEW STAR IN THE CONSTELLATION OF THE SWAN.

tion was it that suddenly produced the incandescence of the sun of the Corona, transforming it from a star of the ninth to one of the second magnitude?

What would become of our planet were such a revolution as this to take place in the sun, and were the calorific and luminous radiation to be suddenly increased a hundred-fold?

PSM V11 D073 Swan constellation spectrum.jpg
Fig. 2.—Spectrum of the New Stab in the Constellation of the Swan. (From Cornu.)

But let us come to the new star of the Swan, which is the main object of this article. Here is a very brief narrative of its discovery.

Julius Schmidt, director of the observatory at Athens, recently wrote to M. Le Verrier the following letter:

"On November 11th, at 5h 40m in the evening, I saw a star of the third magnitude in the zenith, near ρ Cygni. Observations with the refractor of the observatory, at 9h 30m, gave the position of the star as follows:
1876. O Right ascension 21h 36m 50.4s
North declination 42° 16’ 30.5"
"The position for the year 1855 would be:
Right ascension 21h 36m 1.2s
Declination 42° 11’ 1"
"It does not occur in the Bonn "Durchmusterung des Himmels." The star is strongly yellow in color. At midnight it was more intense than μ Pegasi (which is set down as of the third magnitude in Heis's catalogue). On November 20th the star was not visible. On the 21st, 22d, and 23d, the sky at Athens was overcast. From November 24th out, it has steadily declined in brightness, and on December 8th the star was a little below the sixth magnitude."

At Paris, too, the sky was almost constantly overcast for some days after the reception of Schmidt's letter. By taking advantage of infrequent and imperfect seasons of clear sky. Prosper Henry succeeded in observing the new star. Compared with the star 915 of Weisse's catalogue (hour 21), it had this approximate position:

1876. O Right ascension 21h 36m 50s
Declination + 42° 16' 34"

It was of the fifth magnitude, and appeared to be of a greenish color, almost blue, as compared with a neighboring star (42,304 of Lalande).

The new star was also observed at Vienna by Littrow. To him