~A GOOD, CASED DOUBLE FRAME SEXTANT by TROUGHTON c.1820~
$1395 USD (1000 GBP) + shipping (OBO)
A good double frame sextant in bright brass by Edward Troughton c.1820 in original case
15 x 12 in. ( 37 x 30 cm).
Country of manufacture
UK and Ireland
A good, double frame 10 inch radius sextant in bright brass by Edward Troughton c.1820. Marked on the 13 inch radius arc circle, “Troughton, London” silver, 970. The T-frame is in perfect condition with the silver, engine divided arc circle running out to 140 degrees. The index arm with magnifier terminating with a vernier controlled by locking screw and adjusted by worm and screw to read to 10 arc seconds (each degree further subdivided by 6ths). The frame sits atop three tapering brass legs in a tripod pattern. Primary rectangular mirror has 50% silvering loss around the edges but the secondary half mirror is perfect. Fore and aft of the mirrors are 3 round and 4 square, coloured filters (all intact). Also included are 4 tubes (one sighting, low power with internal, square grid hairs, medium power and high power-good optics) screwing into the round mounting bracket controlled by internal screw for height adjustment, on square pillar. The shorter tubes are equipped with solar filters. There is a square key for mirror adjustment and a pair of wrenches (spanners) for tightening the frame (rarely survive). The shaped handle is mahogany, as is the case. Re-lined in blue velvet (Victorian), it measures 15 by 12 inches (keystone shaped). Sometime in the DISTANT past, this instrument was sympathetically and professionally re-lacquered but you have to look carefully for signs (it is NOT buffed and polished). The mahogany box comes with both brass hooks and working lock and key. A functional instrument of navigation with extremely accurate bearing readings.
Ask the Dealer
Mark Hacking (Scientifica Opticae Inc.) has been an avid collector/dealer for over 30 years. A former Science teacher, he has an innate love for anything natural or mechanical. Specializing in optical (microscopes, telescopes), surveying, medical, weighing and drawing instruments, he is an active participant of the Scientific Instrument Fair in London. Living in Stratford, Ontario, Canada, with his wife and two children; Mark looks forward to meeting as many fellow collectors as possible, and has a worldwide following on eBay (Sciopti).
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