Abstract
PHOTOGRAPHS OF STELLAR SPECTRA.—Dr. F. McClean is now engaged on a photographic investigation of the spectra of the northern stars down to the third magnitude. About 160 stars will thus be included in the survey. Some of the results, which have been recently communicated to the Royal Astronomical Society, comprise the spectra of twenty-three characteristic helium stars, and photographs of the spectra of six stars of the third magnitude showing the transitions from one type to-another (Monthly Notices, vol. lvi. p. 428). The instrument used is a photographic telescope of 12 inches aperture and 11 feet 3 inches focal length, having an objective prism of the same aperture placed in front of the object-glass. The refracting angle of the prism is 20°. The prism is mounted on a hinged frame, and the cell containing it can be rotated within the frame, so that all necessary adjustments can be effected with facility.
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Our Astronomical Column. Nature 54, 158–159 (1896). https://doi.org/10.1038/054158a0
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DOI: https://doi.org/10.1038/054158a0