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. First English theodolite as described by L.Digges in 1571. Base plate scale divided in 1/2 deg to 360 and with a geometrical square set with compass. Upper sights and scale a later restoration.
1574
National Maritime Museum

. Computer universal dividers indicating weights of globes of various metals corresponding to measurements of points. Brass gilt with steel points. Inscription: Christophorus Schissler faciebat augustae vindelicorum Anno 1580
1580
National Maritime Museum

. The basic trigometre design consists of two graduated arms pivoting at the end of a fixed base. In Danfrie's version, each arm carries a graduated arc for measuring the angles formed with the fixed base. The distance to a point can be computed usin
1580
National Maritime Museum

. Gilt brass with steel hinged tips that pivot. Folds flat to give four faces, each with an engraved scale. [scale 1:] 1-100 non-linear [scale 2:] 1-100 non-linear (shorter than 1) [scale 3:] 1-50 non-linear [scale 4:] 1-12 linear, each unit = 24 mm
1597
National Maritime Museum

. Semi-circle-Brass 2.75" (7cm) radius. Graduated on face 0-180 with signs of zodiac. 0-180. Three scales of months of the year and days in month. On back of semi-circle are 14 scales marked with signs of the zodiac and graduated 12-8-12, 1-4-1, 7-12
1607
National Maritime Museum

. This is a horary quadrant marked with Gunter scales and a shadow square for surveying marked in the top third. Aside from the signature 'J C 1630', it has several unusual inscriptions. The front left shows the initials 'RF' and an im
1630
National Maritime Museum

. This horary quadrant corresponds almost exactly with that described by John Collins in 'The Description and Uses of a Great Universal Quadrant, London, 1658', and John Collins's 'The Sector on a Quadrant' with illustrations engr
1658
National Maritime Museum

. This horary quadrant is made of wood and paper with brass sighting vanes and is held in its original box which also contains a lead plumb bob. Like other dials of this type by Sutton, It is dated 1658, but has had the words ‘New Stile’ added
about 1658
National Maritime Museum

. Eyepiece cap that is made of wood and covered in brown leather. The round cap has a gold dot pattern around the side and the end has a gold motif.
1661
National Maritime Museum

. Objective lens cap that is made of wood and covered in brown leather. The round cap has a gold dot pattern around the side and the end has gold flourishes and an inscription.
1661
National Maritime Museum

Telescope. This Galilean telescope has the name 'IACOB CUNIGHAM' and the date '1661' stamped onto the objective lens cap, making it one of the oldest dated telescopes in Britain. The two draw tubes are made of wood covered in marbled
1661
National Maritime Museum

Horary quadrant with Gunter projection. This is a horary quadrant marked with Gunter scales. The reverse shows a perpetual calendar for the years 1676 to 1703, a very unusual addition to this type of instrument. It is signed 'Ann Shepard fecit in Bri
1676
National Maritime Museum

. Surveying quadrant . This is a horary quadrant marked with Gunter scales and has a shadow square for surveying marked out in the top third of the instrument. It is signed 'A.O.S. fecit 1682' but the maker is unknown. Both sights on the right-h
1682
National Maritime Museum

. sector
1683
National Maritime Museum

. Topographical instrument and sundial with Latin inscriptions.
1695
National Maritime Museum

. This wooden rule is known as a Gunter rule and is inscribed with scales to help with navigational calculations. The scales on the front include a linear scale in inches, a diagonal scale to set exact lengths, scales of leagues, chords, rhumbs, sines, ta
1700
National Maritime Museum

. A broken part of a wooden horizon vane recovered from the wreck of the ‘Stirling Castle’, which ran aground on the Goodwin Sands off the Kent coast during the Great Storm of 1703.
1703 or earlier
National Maritime Museum

. A broken part of a wooden sight vane or shadow vane. Recovered from the wreck of the ‘Stirling Castle’, which ran aground on the Goodwin Sands off the Kent coast during the Great Storm of 1703. Pu
1703 or earlier
National Maritime Museum

. An incomplete wooden staff and four vanes. The vanes are in two parts and are held together by brass pins. The beginnings of the scales are marked ‘al’ for altitude, and ‘co’, for complement, the zenith distance. The vanes are no
1703 or earlier
National Maritime Museum

. Wooden sight vane with an inlaid brass pinhole sight and a brass pressure plate for holding it tightly in place on the thirty degree arc. The instrument was recovered from the wreck of the ‘Stirling Castle’, which ran aground on the Goodwin
1703 or earlier
National Maritime Museum

. The barrel and five draw tubes of this non-achromatic telescope are made of paper. These allow the telescope to open to a length of about 2m. The other fittings are of turned wood. The initials M.R. and a star motif are stamped on the barrel. These prob
circa 1710
National Maritime Museum

. Slide rule Boxwood Double sided, two slides
1713
National Maritime Museum

Bare Needle Type. Surveying compass Magnetic compass in finely turned pearwood box, circular in shape. Graduated 0 to 360 degrees and in points 32. Bare needle.
1713
National Maritime Museum

. This is a horary quadrant marked with Gunter scales. It is signed 'Richard Howd [Howard] fecit 1715'. Howard was a London instrument maker in the early 18th century. The reverse is blank and has therefore not been photographed. Modified Gunter
1715
National Maritime Museum

. The backstaff is made from a lignum vitae frame with boxwood arcs and crossbar, and brass rivets. There is an inlaid boxwood plate on the main strut. The staff also has a boxwood horizon vane and shadow vane. Decorative fleurs-de-lis are stamped in var
1720
National Maritime Museum

. This is a folding horary quandrant made from northern Italian boxwood. It has scales for degrees, hours and signs of the zodiac. The folding format is very unusual. A plain box opens to reveal a square horary quadrant. This example shows Italian hours a
1723
National Maritime Museum

. Clinometer level with crosswire sights. 6.5" bubble level. Limb scale -5° to 45°. Vernier reading to 5' with slow motion screw. A land surveying instrument used to measure vertical angles in the construction of roads or canals or grad
1724
National Maritime Museum

. The barrel of this non-achromatic telescope is covered in sharkskin and is decorated with gold tooling. There are four draw tubes, each covered in marbled paper. Gold-tooled stop lines around the draw tubes indicate the optimum working length of the tel
1730
National Maritime Museum

. Backstaff horizon vane
1734
National Maritime Museum

. Backstaff shadow vane
1734
National Maritime Museum

. Sight vane for the backstaff
1734
National Maritime Museum

. The backstaff is made from a lignum vitae frame with boxwood arcs, brass-capped rivets, and a boxwood sight vane, horizon vane and shadow vane, the latter with a Flamsteed lens, which allows the instrument to be used when the sun is obscured by cloud by
1734
National Maritime Museum

. This non-achromatic telescope has a rayskin-covered barrel and four draw tubes made of vellum. The other fittings are brass. Both the objective and eyepiece lenses had sliding lens covers, although the cover for the objective lens is now missing. Solid
1736
National Maritime Museum

. The backstaff is made from a lignum vitae frame with boxwood arcs and a boxwood inlaid plate in the main strut, brass rivets, and no vanes. Decorative fleurs-de-lis and stars are stamped on both arcs. The transversal scale on the thirty degree arc is f
1737
National Maritime Museum

. Theodolite in an octagonal wooden box. Base- Diameter 6.5" (16.5cm) is graduated 0-180 by 1 degree in each half, with three verniers, each marked to 30.It is fitted with two knobs, one to turn the instrument in azimuth, the other to clamp it. A tr
1737
National Maritime Museum

. Horary quadrant stand
1738
National Maritime Museum

. This is a horary quadrant but unusually carries no conventional hour lines by which to tell the time. Instead, the front is marked with an astrolabe quadrant. A surveyors shadow square appears as a curved scale along the limb. Unusually for a horary qua
1738
National Maritime Museum

. The octant has a mahogany frame and index arm, boxwood limb, brass fittings and a brass stop for the index arm. There is no tangent screw and the clamping screw, which is broken and possibly an old replacement, is on the back of the index arm. The octan
circa 1750
National Maritime Museum

. The octant has a pear-wood frame, limb and index arm; brass fittings and a brass stop for the index arm, with an inlaid ivory plate on the crossbar, and two red socket shades. Index-glass adjustments can be made by a screw and on both horizon glasses by
circa 1750
National Maritime Museum

. The octant is made from a mahogany frame and index arm, with a boxwood limb, brass fittings, a brass stop for the index arm and an inlaid ivory plate on the crossbar. There is no tangent screw and the clamping screw, which is missing, was on the back of
1753
National Maritime Museum

. The octant is made from an ebony frame and limb with a black-lacquered brass index arm and fittings. There are decorative inlaid diamond-shaped ivory pieces in both struts, and a decorated inlaid ivory plate on the crossbar. There is no tangent screw an
1753
National Maritime Museum

. The backstaff has a lignum vitae frame and boxwood scales, an inlaid ivory plate on the main strut, brass rivets, and no vanes. Decorative stars and fleurs-de-lis are stamped on the frame and handle. The transversal scale on the thirty degree arc (crac
1755
National Maritime Museum

. The octant has a mahogany frame and index arm with a boxwood limb, brass fittings and a brass stop for the index arm. An inlaid plate in the crossbar is now missing. There is no tangent screw and the clamping screw, which is broken, is on the back of th
circa 1755
National Maritime Museum

Bare Needle Type. Miners compass in wooden case, fitted with two sight vanes. Graduated from 1-32. Bare needle type fitted with locking device.
1757
National Maritime Museum

Sextant. The sextant has a polished brass frame and limb, with a four-legged brass section on the back for the belt pole mounting. The detachable belt pole is made of brass and wood. The tangent screw and clamping screw, which are modern replacements, are
circa 1758
National Maritime Museum

. Dry compass card Card- Mica coverd with paper, white with black markings, graduated to 32 points and quadrantally in degrees. Has a decorated E point. Needle-Single flat bar needle 6" long, 0.75" wide at centre, tapering slightly towards the
1760
National Maritime Museum

. The octant has a mahogany frame and limb with a brass index arm, fittings, and a brass stop for the index arm. The inlaid ivory plates on the crossbar and on the back of the frame have been replaced by inlaid brass plates, and a brass strip has replaced
1761or earlier
National Maritime Museum

. The octant has a mahogany frame and limb with a brass index arm, fittings, and a stop for the index arm. There is an inlaid ivory plate on the crossbar. There is no tangent screw, and the clamping screw is on the back of the index arm. The socket shades
1761
National Maritime Museum

. Red marble cylindrical plinthwith brass vertical rod attached to it, having a screw at thr top end which is attached to the rectangular brass 'quadrant'. Hour numbers meant to represent Italian hours but are not consistent. This is a horary q
20th century
National Maritime Museum

. The octant has an ebony frame and limb with a brass index arm, fittings, and stop for the index arm. There is an inlaid ivory plate on the crossbar and inlaid decorative ivory diamond-shaped pieces in both struts, one piece of which is missing. There is
1763
National Maritime Museum

. Drawing instrument set Silver and mother-of-pearl instruments Sharkskin silver mounted velvet lined case.
1764
National Maritime Museum

. Mariners used dividers for measuring distances on charts. This pair is made of wood, with a brass screw and fixing plate and steel points. The year 1766 is roughly inscribed on the handle, as are a number of other motifs, possibly someone’s initia
1766
National Maritime Museum

. The octant has a mahogany frame, limb and index arm, with brass fittings, and a brass stop for the index arm. It also has an inlaid ivory plate on the crossbar. There is no tangent screw and the clamping screw is on the back of the index arm. The octant
1770
National Maritime Museum

Bare Needle Type. Pocket compass Silver pocket compass with white enamel dial. Inside the back is the happ mark 1772. Inn original sharkskin case.Besides the usual 32 points, the card is graduated quadrantally. The sliding locking device beneath the handl
1772
National Maritime Museum

Dip circle. Dip circle or dipping needle, made of brass with gold pivots encased in copper. The needle is 12 inches (30.5 cm) long, and the circular scale is graduated quadrantally to 30 minutes. A dip circle measures the vertical component of the earth&
1772
National Maritime Museum

. Barometer tube mounted in a wooden support.
1772-4
National Maritime Museum

. Label text in note book field. The glass tube is marked NAV0790.1 and can be found via the Whole/Part toggle. Domestic cistern barometer in mahogany frame. Brass scale. Width 4" (10.2 cm)
1772-4
National Maritime Museum

. The octant has a mahogany frame and limb with a brass index arm, and fittings. The back of the limb is also brass-covered and there is a wooden pad-shaped handle on the back of the frame. The clamping screw and tangent screw, which are both missing, are
circa 1772
National Maritime Museum

. Base of case for the achromatic telescope has a tortoiseshell barrel,
1774
National Maritime Museum

. Lid of case for the achromatic telescope has a tortoiseshell barrel.
1774
National Maritime Museum

. Paper. Printed compass card. Decorated North point. Graduated to points and quadrantally in degrees.
1774
National Maritime Museum

. This achromatic telescope has a tortoiseshell barrel, a single draw tube and silvered brass fittings. Its original rayskin-covered case also survives. The eyepiece has a thumbwheel, allowing the observer to select one of four numbered lenses of differen
1774
National Maritime Museum

. The octant has a hornbeam frame and limb with a brass index arm, fittings, and a brass stop for the index arm. There is no tangent screw and the clamping screw is located on the back of the index arm. The octant has two index shades, one in blue and the
1775
National Maritime Museum

. This achromatic telescope has a tapering mahogany barrel and a single brass draw tube. The other brass fittings include a pivoted eyepiece cover and a brass objective lens cap attached to the barrel collar with a chain. There is also a green baize cover
1775
National Maritime Museum

. The octant has a mahogany frame and limb with a brass index arm, fittings, and a brass stop for the index arm. It also has inlaid ivory plates on the crossbar and on the back of the frame. There is no tangent screw and the clamping screw is located on t
1777
National Maritime Museum

. The ebony staff and the four vanes are missing. The sky-end of the staff is pyramid-shaped. The scales are from 90° to 38° (side one); from 90° to 28° (side two); from 90° to 13° (side three) and from 90° to 6° (side fou
1779
National Maritime Museum

. The octant has an ebony frame and limb with a brass index arm, fittings, and a brass stop for the index arm. It also has decorative diamond-shaped inlaid ivory pieces in both struts, as well as inlaid ivory plates on the crossbar and on the back of the
1779
National Maritime Museum

. Lid for the box containing the Amplitude compass
1780
National Maritime Museum

. Magnetic compass designed for measuring the sun's amplitude. The compass card is manuscript and hand-coloured. The North point is indicated with a coat of arms, and the East point is also slightly embellished. The card is graduated to 32 points and
1780
National Maritime Museum

. Sample of putty.
1780
National Maritime Museum

. Side panel for a compass box made of wood with a piece of red glass inset roughly centre.
1780
National Maritime Museum

. Side panel for a compass box made of wood with an incised diamond motif.
1780
National Maritime Museum

. Side panel for a compass box made of wood with an incised diamond motif.
1780
National Maritime Museum

. The octant has a mahogany frame and limb with a brass index arm, fittings, and a brass stop for the index arm. It also has inlaid ivory plates on the crossbar and on the back of the frame. There is no tangent screw and the clamping screw is on the back
1783
National Maritime Museum

. Bowl-Brass, patented by Kenneth Mc Culloch in 1788. Mounted on pivot, the base of bowl coned upwards for the purpose. The bowl is fixed in bracket with two curved slotted arms, in which two pins fixed to the bowl engage, preventing movement in azimuth.
1788
National Maritime Museum

. The marine sextant was developed in the late 1750s. It was used to make observations of the moon and sun. The angle is read off the curved scale at the bottom of the instrument and the scale on the arm, and allowed the navigator to estimate the latitude
1791
National Maritime Museum

. The octant has a mahogany frame and limb with a brass index arm, fittings, and a brass stop for the index arm. It also has inlaid ivory plates on the crossbar and on the back of the frame, which is missing. There is no tangent screw and the clamping cre
1791
National Maritime Museum

. This dry card compass has a paper card (diameter 8.25 inches) marked in points and degress (0-90 in each quadrant). In addition there is a metal rim, also marked in degrees. The card is printed with the name of the inventor, Thomas Smith, and of the mak
1791
National Maritime Museum

. The octant has an ebony frame and limb with a brass index arm and fittings.The brass stop for the index arm is missing and the hole has been filled in. The octant also has inlaid ivory plates on the crossbar and on the back of the frame. A tangent screw
1795
National Maritime Museum

. Eyepiece for box sextant.
1796
National Maritime Museum

Pocket sextant. The sextant is composed of semi-circular polished brass plates with on one side a sliding shutter, and on the other side a hinged plate. The index arm is moved along a tangent screw by a detached milled key shipped in the upper plate. The
circa 1796
National Maritime Museum

. Bowl- Copper with a lead balancing weight at base, inside of bowl painted white. four lubberlines are fitted, consisting of copper strips with a line cut in each. The glazed verge ring, dia. 11.25" (28.6cm) is fitted with an azimuth sight consistin
1798
National Maritime Museum

. The octant has an ebony frame and limb with a brass index arm, fittings, and a brass stop for the index arm, which is now missing. It also has inlaid ivory plates on the crossbar and on the back of the frame, which is missing. The tangent screw, with it
1806
National Maritime Museum

. Bowl: Brass painted black. Set in double gimbals. Lead weight at base. Glazed with brass centre stud. Has spring cover over filling hole. Steadying mechanism attached to box at base. Card: Two concave copper plates soldered together with needle inside
1813
National Maritime Museum

. Case for the Islamic quadrant.
1813
National Maritime Museum

. This circle is made of brass and has fore and back sights. The fore sight consists of a tall hinged open arch with sighting thread (missing) and a short celestial reflector. The back sight is fixed and consists of a curved bracket containing a small pri
1813
National Maritime Museum

. This is an Islamic quadrant. The front is marked with an astrolabic quadrant and the reverse with a sinical quadrant. This instrument is used to both determine the time and to work out Islamic prayer times. Its own case and a compedium of instructions (
1813
National Maritime Museum

. Card- Mica covered with paper, black with white markings, graduated to 1/4 points. Has a decorated E point. Has 6 blobs of sealing to balance card. Needle- Single flat bar needle 6.1" long tapering outwards from expanded centre to 0.75" from e
1816
National Maritime Museum

. Card-Mica covered with paper. Black with white markings graduated to 1/4 points. Decorated East point. Needle- Flat edge bar needle which tapers outwards from the centre to near the ends, where it rounds off gradually to flattened ends, this being a fea
1817
National Maritime Museum

Jennings Insulating Compass. A magnetic dry-card compass of a type patented by Henry Jennings in 1818 (no. 4259). The compass bowl is made of brass. The card is mica covered with paper, and is marked in points, with a fleur-de-lys at north. The unusual
about 1818
National Maritime Museum

. Card-Mica covered with paper. Black with white markings graduated to 1/4 points. Decorated Est point. Needle-Flat edge bar needle which tapers outwards from the centre to near the ends where it rounds off gradually to flattened ends, this being a featur
1819
National Maritime Museum

. Bowl-Copper, fitted with a stop mechanism consisting of a card lifter operated from the bottom of the bowl. Lubber line engraved on ivory plate attached to inside of bowl. Base weighted with lead. roughly cut glass, lossely laid on top. Fitted with bras
1820
National Maritime Museum

. Box
1820
National Maritime Museum

. Brass measuring scale. Fitted wooden box. Inscribed 'S.5' (Hydrographic Office numbering)
1820
National Maritime Museum

. Card- clear mica with narrow rim and cross piece of green paper, graduated in black to 360 degs with two rows of figures, inner row erect for reading on edge of card nearest to observer, outer row very small and inverted for reading by prism. Needle- Fl
1820
National Maritime Museum

. Card-Mica covered with paper, white with black markings, graduated to 1/4 points.It is perforated by eight circular holes irregularly spaced. A slot 6.5" long, 0.7" wide with expanded centre, 1.6" diameter, is cut in the N-S line of card,
1820
National Maritime Museum

. The boxes are marked ACO0046.1-2 and can be found via the Whole/Part toggle. Bowl-Dia. 7" (17.8cm) Black painted brass, balancing weight attached to bottom of bowl. Inside of bowl painted white with a black lubber line painted on side. Mounted in a
1820
National Maritime Museum

. This dry card compass has a brass bowl with a red painted metal piece on the base to add stability, a domed glass cover and is hung in gimbals. The lubber line inside the bowl is a single wire, with a brass band on the opposite side of bowl with vertica
1820
National Maritime Museum

. This dry card compass has a copper and brass bowl outer mounted in gimbals and has a folding lubber point. The pivot is made of steel and is where the inner bowl rests. Its diameter is 3.5" (8.8cm). The inner part of the bowl is made of brass and c
1820
National Maritime Museum

. Two screws for bearing plate compass
1820
National Maritime Museum