Abstract
JANSOK'S STAR OF 1600.—The so called Nova of 1600, which is 34 Cygni of Flamsteed, and P Cygni of Schönfeld's catalogues of variable stars, was discovered by Wilhelm Janson, a pupil of Tycho Brahe's, and entered upon his globe in that year. It has been erroneously stated in sjme astronomical works (as in Cassini's “Elements d'Astronomie) that Kepler was a co-discoverer of this star, of which he himself informs us to the contrary in his treatise, “De Stella tertii honoris in Cygno, quæ ad annum MDC fuit incognita necdum extinguatur, Narratio astronomica”; this is appended to his well-known work, “De Stella nova in pede Serpentarii,” published at Prague in 1606. At p. 154 we read, “Cum mense Majo anni 1602 primum literis monerer de novo Cygni phsenomeno,” &c., while at p. 164 Kepler says distinctly that Janson was the discoverer, “Primus est Gulieimus Jansonius, qui hanc novam a se primùm anno 1600, conspectam profitetur inscriptum in globum cælestem anno 1600 edituin factâ.” Kepler gave the position of the star for the end of 1600 in R.A. 300° 46′, Decl. + 36° 52′. He observed it during nineteen years, it became fainter in 1619, and disappeared in 1621, though Fortuni Liceti dates a reappearance in the same year. In 1655 Dominique Cassini observed it again; it increased during five years, until it attained the third magnitude, and afterwards diminished. On the testimony of Hevelius, it reappeared in November, 1665, it was again faint in the following year, but subsequently brightened without reaching the third magnitude, in 1677 and 1682, it was only of the sixth magnitude. Cassini says on June 24, 1715, a star of this magnitude was seen in the position of P (Bayer) equal to the three which are near that marked b in Cygnus by Bayer.
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Our Astronomical Column . Nature 23, 276 (1881). https://doi.org/10.1038/023276a0
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DOI: https://doi.org/10.1038/023276a0