Thomas Henderson 
Astronomical Observations Made at the Royal Observatory, Edinburgh 
From October 1834 to December 1835

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Couverture du Thomas Henderson: Astronomical Observations Made at the Royal Observatory, Edinburgh (PDF)
Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. The process of reversing the instrument is conveniently and safely per formed by means of an apparatus, which allows the counterpoises to act before the pivots touch the Y’s, so that no additional pressure is exerted upon them, and the instrument is replaced without the least collision. Five vertical Wires and one horizontal Wire of spider-thread are placed in the eye-end of the telescope, besides other two vertical Wires, which are fixed to the same frame, and move together by means of a micrometer screw. The Telescope has four eye-glasses, whose magnifying powers are 100, 136, 200, and 300; but 200 is the power commonly used. For faint objects, the power 136 is applied. The whole aperture of the object-glass is employed, ex cept in observations of the Sun, when it is contracted to inches, and the ih strument screened from the solar rays.
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Langue Anglais ● Format PDF ● ISBN 9780259703402 ● Maison d’édition Forgotten Books ● Publié 2019 ● Téléchargeable 3 fois ● Devise EUR ● ID 5572791 ● Protection contre la copie Adobe DRM
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