Abstract
ON April 27 a number of astronomical exhibits were on view at the meeting of the British Astronomical Association held at Zion College. It would be impossible to describe all of these, but three were of sufficient interest to merit short notices in the May issue of the Association's Journal. Mr. D. A. Campbell showed an ingenious drive for small telescopes. This consisted of a sand-clock, a device at the base of the apparatus regulating the flow of well-sifted silver-sand. A piston of lead rested on the top of the sand, and this, as it sank, pulled a cord which finally actuated the driving shaft of the telescope. Dr. J. L. Haughton exhibited a microscope which measured star images. The main object of the instrument was to determine stellar magnitude by measuring the diameter of the photographic images, and for this purpose an accurately machined screw thread just over 1 cm. in length was used. Mr. A. Coleman showed a solar eyepiece attachment, and has a fairly long description of the apparatus, which should be read by those who are interested in solar work. It minimizes certain disadvantages which are inherent in the usual combination of a solar diagonal with a suitable dark glass over the eyepiece.
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Astronomical Exhibits. Nature 141, 1049 (1938). https://doi.org/10.1038/1411049b0
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DOI: https://doi.org/10.1038/1411049b0