Sextant - Potter, London, circa 1853

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Summary:: Sextant by J. D. Potter, London, in wooden case.

This is probably the sextant that was in use at Williamstown Observatory from February 1854. The Victorian Government had ordered a number of instruments for the Observatory in 1853, including a sextant by Potter, a 30 inch transit instrument by Potter, and a regulator clock by Frodsham (no 880). This sextant replaced the two 'indifferent sextants' used by astronomer Robert Ellery when he established Williamstown Observatiry in 1853 (see ST 22156 for the sextant by Hoppe). Also used at Melbourne Observatory.
Description:: Brass sextant in fitted wooden box, two interchangeable eye pieces, two filters. Graduated to 150 degrees. Black scale inset. Arm has brass vernier and microscope.
Acquisition Information:: Transfer from Melbourne Observatory, 1945

Discipline:	Technology
Dimensions:	9 cm (Height), 26 cm (Width), 22 cm (Length)

Tagged with:	navigation apparatus instruments, sextants, surveying apparatus instruments
Themes this item is part of:	Williamstown Observatory, 1853-1863, Melbourne Observatory Collection, Engineering Collection, Science & Measurement Collection, Transport Collection, Positional Astronomy at Melbourne Observatory, Weights & Measures at Melbourne Observatory, Melbourne Observatory & Standard Time in Victoria, Melbourne Observatory & Standard Time in Victoria, Astrographic Catalogue, Transits of Venus, 1874 & 1882, Buildings at Melbourne Observatory, Star Observations & Personal Equation, Meteorology at Melbourne Observatory, 1863-1908, Melbourne Observatory, 1863-1944, Geodetic Survey of Victoria, 1858-1872, Geodetic Survey of Victoria, 1858-1872
Primary Classification:	SURVEYING & NAVIGATION
Secondary Classification:	Optical
Tertiary Classification:	angular measurement
Inscriptions:	Scale inscribed 'J. D. Potter, Poultry, London'. Label in lid inscribed 'J. D. Potter, Hydrometer and Mathematical Instrument Maker'.
Maker:	John Potter, London, Middlesex, England, Great Britain, 1853
User:	Melbourne Observatory, South Yarra, Victoria, Australia
User (Probable):	Williamstown Observatory, Williamstown, Victoria, Australia, 1854-1863 See R.L.J. Ellery, 'Account of Operations Connected with the Advancement of Commercial Astronomy in Australia', Monthly Notes & Records of the Royal Astronomical Society, 1854/55, No.15, pp.153-156 (p.154).