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Lunar octant, Captain Laurent's patent No. 25, 1870-1879

lunar octant

INSTRUMENTS - OCTANTS
Laurent
1870-1879
arc 10 in.

Lunar vernier octant; brass frame, arc and arm; ivory scale; wooden handle. Dated 1870s. Two sets of shades; lenses missing from telescope. Inscribed on arc: "CAPTAIN LAURENT'S PATENT (No. 25)." Equipped w/astigmatizer which changed star's image from a point to a horizontal line, therefore lessening the error in observing the star on the horizon correctly. Sighting telescope is missing its large objective lens which would give a brighter view of night horizon. Measures to 102°. [See Willem F.J. Mörzer Bruyns ‘The Introduction of the Elongating Glass on Sextants’. In: Rittenhouse, 10,3 (1996) 71-80.]


1971.300