Images(10)

Sextant in Original Box

Manufacturer Henry Hughes & Sons Ltd.

Date10 July 1945

Period20th century

Classification(s)

Navigation and Timekeeping / Magnetic and Astronomical

Object TypeSextant

Registration NumberMMM 000073.5

DescriptionSextant in original box with accessories. The mahogany box has two hooks for closure and a key hole on the front, as well as a handle on the left-hand side. On the interior, the box is covered in green padding material. The lid has a manufacture note and instruction plaque (see Inscriptions). The sextant has a "HUSUN Trademark" mark on it, and is inclusive of accessories including key tied to a string, cloth and a small Glass bottle of whale oil. The sextant has a black powder-coated finish, whilst the traditional inlaid silver scale is marked from -5 to 150 degrees in single increments. It has a mirror adjusting tool and a screw-on eyepiece sun filter.

The word 'sextant' was developed from the actual arc of the frame which occupies a sixth of a circle, and it was a development from the octant. The need to have an instrument measuring up to 120 degrees arose from the observations determination of longitude. The sextant is useful to read horizontal angles and, its all metal construction makes it more accurate than a wooden octant (Baddeley 1993: 50).
InscriptionsInterior of the lid an illustrated note with logo "HUSUN - Registered Trademark Henry Hughes & Son Ltd London" in between two mermaids holding an entwined rope. The note reads "The Sextant No. 48725 named Henry Hughes & Son, Ltd. of 6" radius & reading to 10" has been examined & found satisfactory. The following corrections should be applied:- Angle - 30 degrees - 60 degrees - 90 degrees - 120 degrees; Correction -10" - -30" - -30" - 0". The shades and mirrors are satisfactory. Telescope data:- Magnification 2 1/2X - Angle of Field of View 7 degrees - Effective Aperture 1.22". The definition is satisfactory. Date 10/7/45 and signed. Interior of the lid, metal plate reads "IMPORTANT In order to maintain the accuracy of this sextant, we recommend your attention to the following: 1. Keep the working parts regularly lubricated with the special oil provided. This should be sparingly applied to the underside of the large micrometer pivot screw. The micrometer screw bEarrings, and also to the rubbing surfacres of the arc. 2. The arc anomometer teeth must be kept clean in order to prevent stiffness developing in the index bar movement. 3. Do Not apply excessive pressure to the mirrors when cleaning them". On sextant "Made in Great Britain".Annotations and MarksOn Sextant, marked "Husun Trademark"Material

Wood, metal, Glass

DimensionsWooden case: 22.5 x 27.5; Sextant: 13 x 26.7cmPublished Referenceshttps://www.rmg.co.uk/collections/objects/rmgc-object-43400
Bibliography

Baddeley, J. (1993). 'Nautical Antiques & Collectibles', London: Sotheby's Publications.

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