Abstract
THE DOUBLE-STAR α HERCULIS.—Smyth, in his “Cycle of Celestial Objects,” attributes to Sir William Herschel the discovery of the duplicity of this star; but the companion was detected two years earlier than Sir William's first observation, and under somewhat curious circumstances. It was perceived by Maskelyne while observing the meridian passage on August 7, 1777, and only seven days later Christian Mayer, also observing the transit of the star with his mural quadrant, noted it to be double. The particulars are detailed in Mayer's work, “De Novis in Cœlo Sidereo Phenomenis,” published at Mannheim in 1779. He had communicated to Maskelyne a number of his results bearing upon the double-stars; and the Greenwich astronomer, in replying towards the end of 1777, relates that he had observed a similar phenomenon in α Herculis on the date given above, “et videns valde obstupui,” he remarks, since he had so often observed the star on the meridian without perceiving the companion. Maskelyne considered it of the sixth magnitude, the principal star being estimated a third; the latter he judged to be reddish, and the companion pale; Mayer, who discovered the smaller star on August 14, called it a seventh or eighth magnitude.
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Our Astronomical Column . Nature 29, 536–537 (1884). https://doi.org/10.1038/029536a0
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DOI: https://doi.org/10.1038/029536a0