This representative example demonstrates a mariner’s astrolabe. Historical examples are rare. There are less than one hundred known to exist and most of these have been recovered from shipwrecks, many from Spanish and Portuguese vessels. An astrolabe is a measuring device once used to navigate the seas by observing the sun and stars to measure their altitude. The measurement of altitude could then be used to calculate the ship’s latitude but at that time in history there was no means of measuring longitude. The body of the navigational astrolabe was cast brass and much heavier, and less complicated than the variety used on land. The heavier weight and cut-away shape reduced the effect of the wind and waves when trying to use it at sea. A mariner’s astrolabe or ‘star finder’ is a simplified version than that used by Arabic astronomers to find the altitude of the sun and stars above the horizon, and time of the sunrise and sunset. It is a forerunner to the quadrant, octant and sextant and was popular for about 200 years over the 1500s and 1600s to find the latitude of a ship at sea. The user held the astrolabe at eye level and, usually with assistance, aligned the stars through the two small sights (pinnules), then read the altitude indicated by the pointer on the arm. It could also be used to sight the sun by holding it lower down, aiming it at the sun, and adjusting it until the sun shone through both pinnules. This astrolabe is an example used to demonstrate the mariner’s astrolabe, which was navigational tool of the 1500s and 1600s, in the time before longitude was able to be determined. It is a forerunner to modern navigation technology. Mariner’s astrolabe – a representative example. A gold painted, disc shaped object with cut outs and revolving arm in centre. The arm has two sights attached at right angles. The top has a ring attached. Measurements are marked in degrees in a circular scale around outer edge.flagstaff hill, warrnambool, maritime village, maritime museum, flagstaff hill maritime museum & village, shipwreck coast, great ocean road, navigation instrument, navigation tool, navigation, astrolabe, mariner’s astrolabe, measure latitude, measure altitude, arabic navigation, measuring device, star finder, astronomy, marine tool, marine instrument

A sextant is an astronomical instrument used to determine latitude and longitude at sea by measuring angular distances, especially the altitudes of the sun, moon, and stars. It is a doubly reflecting navigation instrument and used mainly by sailors to measure the angular distance between two visible objects. The name comes from the Latin sextans, or “sixth part of a unit,” because the sextant’s arc can be 60° or 120° of a circle depending on the model used. The primary use was to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle is known as sighting or shooting the object, or taking a sight. This angle and the time when it was measured is used in order to determine Greenwich Mean Time and hence longitude. Sighting the height of a landmark on land can also give a measure of distance from that object. History: The development of the sextant was as an improvement over the octant, an instrument designed to measure one's latitude. The octant was first implemented around 1731-present but can only measure angles up to 45°. As larger angles were needed to allow the measurement of lunar objects - moon, stars and the sun - at higher angles, the octant was superseded by the sextant. The sextant is a similar instrument but better made and allows larger angles from 60° to 120°. This improvement allows distances to be accurately calculated thereby giving longitude when used with a chronometer. The sextant was derived from the octant in 1757, eventually making all previous instruments used for navigational positioning obsolete. The sextant had been attributed to by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but reference to the sextant was also found later in the unpublished writings of Isaac Newton (1643–1727). Earlier links can be found to Bartholomew Gosnold (1571–1607) indicating that the use of a sextant for nautical navigation predates Hadley's implementation. In 1922, the sextant was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho. It should be noted that the octant and quadrant are in the same family as they were, and all are, regarded as sextants. The sextant is representative of it's type and although not fully complete it demonstrates how 18th,19th and 20th century mariners determined their latitude and longitudinal to determine their position on a chart, allowing them to navigate there way across the world's oceans. It also demonstrates the skill and workmanship of the early instrument makers that operated scientific instrument businesses from London and other areas of England to provide most of the navigational instrumentation used by commercial and military navies of the time.Sextant with square, fitted box of polished wood, "Hezzanith" brand. Box contains many parts for the sextants use. On certificate "Heath & Co, London. Sextant Number Y 822". Catch on lid "DEFIANT LEVER" and "PATENT NUMBER 187.10". Maker's certificate is attached to the inside of the box.flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, sextant box, sextant, hezzanith, heath & co, navigational instrument, george wilson heath, astronomical instrument, instrument manufacturers, scientific instrument, navigation, celestial navigation, octant, quadrant, lunar navigation

An Octant is a doubly reflecting navigation instrument used primarily by sailors to measure the angular distance between two visible objects and was a forerunner of the sextant. The name comes from the Latin octo, or “one-eighth of a circle,” for the Octant’s arc which spans 45°, or one-eighth of a circle. The primary use of an Octant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical chart (latitude), for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) gives an angle by which the latitude can then be estimated. Sighting the height of a landmark on land can also give a measure of distance. History: The principle of the Octant as an instrument to measure ones latitude was first implemented around 1742-present but was superseded by the improvement of the octant to a sextant, a very similar instrument, better made and able to measure bigger angles 120°, allowing the measurement of Luna distances to give longitude when used with an accurate chronometer. The sextant started to appear around 1730 and had been attributed to by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but reference to the sextant was also found later in the unpublished writings of Isaac Newton (1643–1727). Earlier links can be found to Bartholomew Gosnold (1571–1607) indicating that the use of a Sextant for nautical navigation predates Hadley's implementation. In 1922, the sextant was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho. Henry Hemsley was a lesser-known instrument maker and optician working in London in the late 17th and early 18th century. However, it should be noted that there were two Henry Hemsley opticians and instrument makers around this period. (Henry Hemsley 1, 1786-89, who had premises at 85 Fleet St London and Henry Hemsley 2, 1828-56), whose workshop was at 135-138 Radcliff Highway London. Therefore, based on the inscribed workshop address Henry Hemsley 2 is responsible for making this example.The octant is representative of its type and although not fully complete it demonstrates how 18th and 19th-century mariners determined their latitude on a chart to navigate their way across the world's oceans in the 18th and 19th century. It also demonstrates the skill and workmanship of the early instrument makers that operated from London at this time and provided most of the navigational instrumentation use by commercial and military navies of the time.Octant, ebony wooden frame and handle. Scale is missing from recess in frame. "H. Hemsley 135-138 Ratliff Highway, London", no box"H. Hemsley 135-138 Ratcliff Highway, London"flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, navigation, navigational instrument, instrument used for navigation, sextant, henry hemsley, instrument maker, london, octant

This is a set of 30 photographs of Royal Australian Survey Corps (RA Svy) personnel from Central Comd Fd Svy Unit (Adelaide) on Aerodist survey operation - Project C4 in Eastern Arnhem Land, Northern Territory in 1967. Photos of personnel were taken either at the operations base at Numbulwar or the main base at Gove (Nhulunbuy). RA Svy conducted nineteen Aerodist operations for 12 years from 1964 to 1975. Aerodist MRC2 was a tellurometer-based system adapted for aircraft to accurately measure distances between non-intervisible ground survey stations, using the aircraft as an intermediate station. Lower order geodetic results could be achieved by survey network trilateration. The measured distances between stations formed survey networks from which each station’s latitude and longitude was computed. Aerodist MRC2 was RA Svy’s major horizontal control survey tool for mainly medium scale topographic mapping (scale 1:100,000 Class A being spatially accurate to within 50 metres) in PNG, northern NT, north-west WA, Kalimantan Barat (West) Indonesia, Sumatra Indonesia, Gulf of Carpentaria and Cape York, QLD. In 1967, the Aerodist MRC2 Master equipment was installed in the aircraft featured in this set of photos, Executive Air Services’ (Essendon VIC) Grand Aero Commander VH-EXX. It was the same aircraft type and company contracted to Division of National Mapping for Aerodist MRC2 surveys. From July to October 1967 the aircraft was attached to Central Comd Fd Svy Unit (Adelaide - Major Don Ridge) on Project C4 eastern-Arnhem Land NT, where 317 Aerodist lines measuring 17,300 line miles were successfully completed. This was the most productive Aerodist project thus far. The most common helicopter used by RA Svy up to 1972 was the civilian Bell 47G-2 and the Sioux Light Observation Helicopters (LOH), the Australian Army’s equivalent featured in this photo set. These light observation helicopters had a limiting load carrying capacity of up to about 500 pounds. By comparison, one Aerodist team including two people weighed up to 1,500 pounds. Source: Royal Australian Survey Corps – Aerodist Years 1964-1975 by Peter Jensen. Refer to Item 9061.26P for more photos taken during this Aerodist survey operation.This is a set of 30 photographs of Royal Australian Survey Corps (RA Svy) personnel on Aerodist survey operations in Eastern Arnhem Land, Northern Territory in 1967. The photographs are on 35mm negative film and scanned at 96 dpi. They are part of the Army Survey Regiment’s Collection. .1) to .4) - black & white, 20th August 1967, Project C4 Aerodist Operations Base - Numbulwar, NT. .5) - Photo, black & white, 1967. Probable wrecked Indonesian fishing vessel. .6) to .8) - Photo, black & white, 1967. Unidentified survey operations base, L to R: unidentified personnel. .9) - Photo, black & white, 1967. Unidentified survey operations base, unidentified soldier driving a Haflinger 4x4 Light utility vehicle. .10) - Photo, black & white, 1967. Unidentified survey operations base, L to R: unidentified technician. .11) - Unidentified technician reading two survey altimeters to compute corrections to the measured distances for atmospheric refraction and to compute the sea level distances from the slope distances aircraft to the ground stations. .12) - Photo, black & white, 1967. Survey operations base, L to R: unidentified (x3), W01 Pat Wood BEM, unidentified. .13) to .16) - Photo, black & white, 1967. Unidentified personnel operating remote Aerodist MRC2 ground instruments. .17) to .18) - Photo, black & white, 1967. Unknown RA Svy office location. .19) to .20) - Photo, black & white, 1967. Aerodist MRC2 Master equipment. .21) to .22) - Photo, black & white, 1967. Aero Commander VH-EXX probably at Gove, NT, Central Comd Fd Svy Unit (Adelaide) – OC Major Don Ridge. .23) to .25) - Photo, black & white, 1967. Aero Commander VH-EXX probably at Gove, NT. Unidentified personnel. .26) - Photo, black & white, 1967. Aero Commander VH-EXX probably at Gove, NT. Aerodist antenna pods are visible on the aircraft. .27) to .29) - Photo, black & white, 1967. Australian Army Sioux Light Observation Helicopter (LOH) probably at Gove, NT. .30) - Photo, black & white, 1967. Panelled U337 survey station, visible as a white cross on aerial identification photo..1P to .2P – date and location on edge of film negative. .5P to .28P – no annotations .29P - annotated in white ‘RW-JEP Gove NT’ .30P - annotated in white ‘U337 Spool No1 Jun67’royal australian survey corps, rasvy, army survey regiment, army svy regt, fortuna, asr, aerodist, surveying, central comd fd svy unit

This is a set of 26 photographs of Royal Australian Survey Corps (RA Svy) personnel from Central Comd Fd Svy Unit (Adelaide) on Aerodist survey operation - Project C4 in Eastern Arnhem Land, Northern Territory in 1967 (photos .4P to .26P) and in Western Arnhem Land, Northern Territory in 1968 (photos .1P to .3P). Photos of personnel were taken either at the operations base at Numbulwar or the main base at Gove (Nhulunbuy). RA Svy conducted nineteen Aerodist operations for 12 years from 1964 to 1975. Aerodist MRC2 was a tellurometer-based system adapted for aircraft to accurately measure distances between non-intervisible ground survey stations, using the aircraft as an intermediate station. Lower order geodetic results could be achieved by survey network trilateration. The measured distances between stations formed survey networks from which each station’s latitude and longitude was computed. Aerodist MRC2 was RA Svy’s major horizontal control survey tool for mainly medium scale topographic mapping (scale 1:100,000 Class A being spatially accurate to within 50 metres) in PNG, northern NT, north-west WA, Kalimantan Barat (West) Indonesia, Sumatra Indonesia, Gulf of Carpentaria and Cape York, QLD. In 1967, the Aerodist MRC2 Master equipment was installed in the aircraft featured in this set of photos, Executive Air Services’ (Essendon VIC) Grand Aero Commander VH-EXX. It was the same aircraft type and company contracted to Division of National Mapping for Aerodist MRC2 surveys. From July to October 1967 the aircraft was attached to Central Comd Fd Svy Unit (Adelaide - Major Don Ridge) on Project C4 eastern-Arnhem Land NT, where 317 Aerodist lines measuring 17,300 line miles were successfully completed. This was the most productive Aerodist project thus far. The most common helicopter used by RA Svy up to 1972 was the civilian Bell 47G-2 and the Sioux Light Observation Helicopters (LOH), the Australian Army’s equivalent featured in this photo set. These light observation helicopters had a limiting load carrying capacity of up to about 500 pounds. By comparison, one Aerodist team including two people weighed up to 1,500 pounds. In 1968, after completion of the Kimberley Aerodist Operation project, the Aerodist system in VH-EXX was immediately deployed to western-Arnhem Land NT for Central Comd Fd Svy Unit (Adelaide - Major Don Ridge) to complete the mapping control across northern NT from mid-July to October. The Aerodist MRC2 Remote antenna seen in Photos .24P to .26P is mounted on a 20 foot pole tower. The antenna direction was controlled by wires/ropes to the two arms under the dish at right angles. The antenna elevation could be changed to the vertical for aircraft height checks as seen in photo .25P. Source: Royal Australian Survey Corps – Aerodist Years 1964-1975 by Peter Jensen. Refer to Item 6449.30P for more photos taken during these Aerodist survey operations.This is a set of 26 photographs of Royal Australian Survey Corps (RA Svy) personnel on Aerodist survey operations in Eastern Arnhem Land, Northern Territory in 1967 and Western Arnhem Land, Northern Territory in 1968. The photographs are on 35mm negative film and scanned at 96 dpi. They are part of the Army Survey Regiment’s Collection. .1) to .2) – Photo, black & white, 1968, unidentified soldier with an opened can of food, possibly bully beef. .3) – Photo, black & white, 15 Aug 1968, aerial view of terrain taken from a helicopter in vicinity of MILINGIMBI SIERRA. .4) – Photo, black & white, 1967, aerial view of an island taken from a helicopter. .5) & .6) – Photo, black & white, 1967, unidentified soldier driving a Haflinger 4x4 Light utility vehicle with trailer. .7) – Photo, black & white, 1967, unidentified surveyors taking vertical measurements with a leveling instrument and staff. .8) – Photo, black & white, 1967, Australian Army Sioux Light Observation Helicopter (LOH) with float removed. .9) to .11) – Photo, black & white, 1967, Australian Army Sioux Light Observation Helicopter (LOH) with floats. .12) – Photo, black & white, 1967, civilian Bell 47G-2 helicopter (Australian Army Sioux LOH equivalent) refuelled. .13) – Photo, black & white, 1967, survey station on coastline surrounded by white plastic aerial photographic identification panels lined with rocks. .14) & .15) – Photo, black & white, 1967, soldier (possibly a signaller from RA Sigs) operating a radio. .16) – Photo, black & white, 1967, Central Comd Fd Svy Unit Operations Section tent, Main Base Gove (Nhulunbuy) L to R: SPR Harry Dunn, WO1 Pat Wood BEM. .17) – Photo, black & white, 1967, Central Comd Fd Svy Unit Operations Section tent, Main Base Gove (Nhulunbuy) L to R: unidentified, WO1 Pat Wood BEM. .18) – Photo, black & white, 1967, Central Comd Fd Svy Unit Operations Section, Main Base Gove (Nhulunbuy), unidentified Australian Army Catering Corps cook preparing meals. .19) – Photo, black & white, 1967, Central Comd Fd Svy Unit Operations Section, Main Base Gove (Nhulunbuy) mess tent in readiness for meals. .20) – Photo, black & white, 1967, Bank of batteries in transit boxes undergoing recharging using generators. .21) – Photo, black & white, 1967, A topographic survey identification plaque set in a concrete block being weighed using a set of scales hanging from slaughtering gallows. .22) – Photo, black & white, 1967, CPL (Geoff or Gary) Larkin operating the remote Aerodist MRC2 ground instrument at Veronica Island, located north of Nhulunbuy. .23) – Photo, black & white, 1967, L to R: CPL (Geoff or Gary) Larkin with unidentified surveyor operate the remote Aerodist MRC2 ground instrument at Venica Island, located north of Nhulunbuy. .24) & .25 – Photo, black & white, 1967, The Aerodist MRC2 Remote antenna. .26) – Photo, black & white, 1967, The Aerodist MRC2 Remote antenna.The following photos are annotated in black ink on edge of film negative: .3P – ’15 Aug ’68, 2000’, 1-C18 ’68 MILINGIMBI SIERRA’ .4P – ’U462’ .8P – ‘1-C3/67 Float Removed’ .13P – ‘U477 10-C3/67 .20P - ‘2-C3/67 Bank of Chargers’ .21P - ‘3-C3/67 Gallows & Scales’ .22P - ‘0462 VERONICA ISLAND NT, CPL Larkin’ .23P - ‘0462 VERONICA ISLAND NT’ .24P - ‘4-C3/67 20’ Aerodist Tower’ .25P - ‘5-C3/67 20’ Aerodist Tower’ .26P - ‘6-C3/67 20’ Aerodist Tower’royal australian survey corps, rasvy, army survey regiment, army svy regt, fortuna, asr, aerodist, surveying, central comd fd svy unit

An hourglass or sandglass is an instrument for measuring a defined time and can be used perpetually by simply turning it over immediately the top bulb empties. The clear blown glass is shaped into two equal sized bulbs with a narrow passage in the centre and contains uniform sized sand or glass particles in the lower bulb. The width of the neck regulates the constant flow of the particles. The glass is held in a stand with top and bottom of equal shape and size. Hourglasses can measure an infinite variety of time by gauging the size of the particles, the shape and size of the bulbs and the size of the passage between the bulbs, thus measuring hours or minutes or even seconds. Generally an hourglass sits between discs of wood at the ends, which are joined by long wooden spindles between the ends and tightened by screw caps. The length of time can be adjusted by adding or removing sand particles. The use of the marine sandglass (or hourglass) has been recorded in the 14th century in European shipping. A one minute sandglass was used in conjunction with the ship’s log for ‘dead reckoning’, (see below) that is, for measuring the ship’s speed through the water. They were also used to regulate ringing the ship’s timetable; for example a 4 hour sandglass was used for the length of the sailors’ watch, and a half hour timer for taking of readings for the ship’s log; the ship’s bell would be rung every half hour. It was usually the role of the cabin boy to watch and turn the sandglasses over at the exact time of them emptying their upper chambers and to ring the ship’s bell. Hourglasses have been used historically for many hundreds of years. Some have been used for timing church sermons, in cooking, in industry and at sea. Even today they are used for measuring the cooking time of eggs and timing a player’s turn in games such as Boggle and Pictionary. The sandglasses at sea were gradually replaced in the late 1700’s to early 1800’s by the more accurate chronometers (marine clocks) when they became reliable instruments. DEAD RECKONING (or Deduced Reckoning) Dead reckoning is the term used to describe the method of calculating the ship’s position from its speed and direction, used in early maritime travel, mostly in European waters. Both the (1) speed and the (2) direction of travel were recorded on a Traverse Board at half-hourly intervals during a helmsman’s watch of 4 hours. The navigator would record the readings in his ship’s log, plot them on his navigational chart and give his updated course directions to the next helmsman on watch, along with the cleared Traverse Board. This was a very approximate, but none-the-less helpful, method of navigation. The wooden Traverse Board was a simple pegboard with a diagram of a compass with eight peg holes along the radius to each of the compass points, plus a grid with ascending half hours in the left column and increasing ship’s speed in knots in a row across the column headings, with a peg hole in each of the intersecting cells. A number of wooden pegs were attached to strings on the board. By placing one peg consecutively in the direction’s radius hole, starting from the centre, and the speed holes when the half hourly reading was taken, a picture of speed and direction for the whole 4 hour watch was created. (1) To measure the ship’s speed a one minute hourglass timer was usually used to measure the ship’s speed through the water and help to calculate its longitude. A rope, with knots at regular standard intervals and a weight such as a log at the end, would be thrown overboard at the stern of the ship. At the same time the hourglass would be turned over and a seaman would start counting the number of knots on the rope that passed freely through his hands as the ship travelled. When the timer ran out the counting would be stopped. A timer of one minute (one-sixtieth of an hour), knots spaced one-sixtieth of a nautical mile apart, and simple arithmetic easily gave the speed of the ship in nautical miles per hour ("knots"). This would be recorded every half hour. The speed could however be inaccurate to the travel being affected by ocean currents and wind. (2) To calculate the ship’s direction a compass sighting would be recorded each half hour.Marine hourglasses or sandglasses were used from around the 14th to 19th century during the time of sailing ships. This hourglass is representative of that era, which is during the time of the colonisation of Australia. Hourglass or sandglass; an instrument used to measure time. Two equal sized clear glass bulbs joined with a narrow passage between them, containing equal sized particles of sand grains in lower bulb. Glass sits in a brass collar at each end, in a frame comprising 3 decorative brass columns or posts, each attached top and bottom, using round screw-on feet, to round brass discs. Disc have Roman numerals for the numbers 1 - 12 pressed into their inner surfaces and hieroglyphics on the outer surfaces. Roman numerals on inner surface of discs " I II III IV V VI VII VIII IX X XI XII " Hieroglyphics impressed on outer surface of discsflagstaff hill, warrnambool, shipwrecked coast, flagstaff hill maritime museum, maritime museum, shipwreck coast, flagstaff hill maritime village, great ocean road, horology, hourglass, hour glass, sandglass, sand glass, timing instrument, dead reckoning, deduced reckoning, finding latitude at sea, sandglass with hieroglyphics and roman numerals, hourglass with hieroglyphics and roman numerals, brass hourglass

An octant is an astronomical instrument used in measuring the angles of heavenly bodies such as the sun, moon and stars at sea in relation to the horizon. This measurement could then be used to calculate the altitude of the body measured, and then the latitude at sea could also be calculated. The angle of the arms of an octant is 45 degrees, or 1/8 of a circle, which gives the instrument its name. Two men independently developed the octant around 1730: John Hadley (1682–1744), an English mathematician, and Thomas Godfrey (1704–1749), a glazier in Philadelphia. While both have a legitimate and equal claim to the invention, Hadley generally gets the greater share of the credit. This reflects the central role that London and the Royal Society played in the history of scientific instruments in the eighteenth and nineteenth century's. There were also two others who are attributed to having created octanes during this period, Caleb Smith, an English insurance broker with a strong interest in astronomy (in 1734), and Jean-Paul Fouchy, a mathematics professor and astronomer in France (in 1732) In 1767 the first edition of the Nautical Almanac tabulated lunar distances, enabling navigators to find the current time from the angle between the sun and the moon. This angle is sometimes larger than 90°, and thus not possible to measure with an octant. For that reason, Admiral John Campbell, who conducted shipboard experiments with the lunar distance method, suggested a larger instrument and the sextant was developed. From that time onward, the sextant was the instrument that experienced significant development and improvements and was the instrument of choice for naval navigators. The octant continued to be produced well into the 19th century, though it was generally a less accurate and less expensive instrument. The lower price of the octant, including versions without a telescope, made it a practical instrument for ships in the merchant and fishing fleets. One common practice among navigators up to the late nineteenth century was to use both a sextant and an octant. The sextant was used with great care and only for lunar sightings while the octant was used for routine meridional altitude measurements of the sun every day. This protected the very accurate and pricier sextant while using the more affordable octant for general use where it performs well. The invention of the octant was a significant step in providing accuracy of a sailors latitude position at sea and his vessels distance from land when taking sightings of land-based landmarks.Octant with metal handle, three different colored shades are attached, in wooden wedge-shaped box lined with green felt. Key is attached. Two telescope eyepieces are in box. Some parts are missing. Oval ink stamp inside lid of box, scale is graduated to 45 degrees. Ink stamp inside lid of box "SHIPLOVERS SOCIETY OF VICTORIA. LIBRARY"instrument, flagstaff hill, warrnambool, shipwrecked coast, flagstaff hill maritime museum, maritime museum, shipwreck coast, flagstaff hill maritime village, great ocean road, octant, navigation, nautical instrument, navigation instrument, john hadley, sextant, astronomical instrument

An Octant is a doubly reflecting navigation instrument used primarily by sailors to measure the angular distance between two visible objects and was a forerunner of the sextant. The name comes from the Latin octo, or "one-eighth of a circle," for the Octan'ts arc which spans 45°, or one-eighth of a circle. The primary use of an Octant is to measure the angle between an astronomical object and the horizon for celestial navigation. The estimation of this angle, is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical chart (latitude), for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) gives an angle by which the latitude can then be estimated. Sighting the height of a landmark on land can also give a measure of distance. This fine octant once belonged to Captain Farquhar Chisholm and was donated by his granddaughter, Margaret Ruth Greer (nee Chisholm, born 1914). The label inside the Octant's box reads “Thomas L. Ainsley, Instrument Maker … etc”. Farquhar Chisholm was born in 1832 in Inverness, Scotland. He regularly sailed on perilous voyages between Quebec, Canada and the Baltic ports of Europe. In 1854 he migrated to Australia during the Gold Rush, to a place called Fiery Creek (near Beaufort Victoria) where he was fairly successful in his quest for gold. In the years of the Great Gold Rush, it was said that there were over 40,000 diggers in the goldfields of the Beaufort area! In 1857 having made sufficient money, he hired another crew and returned to Clachnacuddin, Inverness shire, Scotland and in that same year, he studied and obtained his Master Mariner Certificate (which would have included the use of an octant for navigation). He was appointed to Mr George (or James) Walker, as commander of his sailing ship, the 3-masted ELIZABETH, built 1859 and known as “The Walker barque”. In 1870 he married, then in 1887 returned to Australia with his wife and children (Kenneth Chisholm (1871), Mary Bremner Chisholm (1873), Margaret Hood Chisholm (1874), Farquhar Chisholm (1878)). They arrived in Port Melbourne, Victoria and sadly, only six weeks after landing, his wife Caroline passed away (in Geelong,1888). In 1900 Capt. Chisholm lived in Camperdown (Victoria) and not long after this his daughter Margaret died of consumption. In his later years, he went to live in the manse of St. Paul’s Presbyterian Church, Wangaratta, with his son, Rev. Farquhar Chisholm. He died there on Sat, 23rd March 1912, 80 years old. He was known as “… quiet, unobtrusive and competent, respected by all with whom he came in contact”. Some other members of Captain Chisholm’s family are; his older son Kenneth Chisholm, who was a contractor in Camperdown; a nephew Donald Macintosh (of 23 Douglas Row, Inverness); a grandson Brian Jones (son of Caroline Belle-Jones nee Chisholm, who lived in Camperdown in the earlier part of her life).The octant, the forerunner of the sextant, was a significant step in providing accuracy of a sailors latitude position at sea & his vessels distance from land when taking sightings of land-based landmarks.Octant, once belonging to Captain Farquhar Chisholm. Wedge shape (the size of an eighth of a circle), made of wood, glass and metal. Used in the 1880s. Maker’s name across centre “L. SIMON - - - SHIELDS”. Three (3) light filtering, coloured glass shades. Two (2) eyepieces. Scale attached for measuring angles. Label inside the fitted, wedge-shaped case "Thomas L. Ainsley, Optician"Label inside case "Thomas L. Ainsley, Optician" Maker’s name across centre “L. SIMON - - - SHIELDS”.flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, maritime navigation, navigation instrument, migration, captain chisholm, farquhar chisholm, sailing ship, the elizabeths, thomas l. ainsley, l. simons, shields england, octant, john hadley, chisholm

This sextant is very similar to a 1915 Sextant design. A sextant is an astronomical instrument used in measuring angular distances especially the altitudes of sun, moon and starts at sea determining latitude and longitude.This sextant is an example of a 19th-century marine instrument used for finding location at sea. It was made by London scientific instrument maker Troughton and Simms, which originated in 1826 and continued until 1922.Sextant and its fitted square wooden box. The handle of the sextant is carved with a cross-hatched pattern. Made by Troughton and Simms, London.flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, sextant, navigational instrument, marine navigation, marine equipment, instrument, navigation, troughton and simms, london, scientific instrument

This chronometer was made around 1936 and has been on display at Flagstaff Hill for over 40 years as part of the exhibit of the ‘Reginald M’, an Australian-built, 19ss, coastal trader vessel. A chronometer is an accurate mechanical instrument used for measuring time. It is constructed carefully to remain stable even under the changing conditions of seafaring life such as temperature, humidity and air pressure. The Master or Navigator of a ship could use the chronometer and the positions of celestial bodies to calculate the ship’s latitude at sea. In 1905 the business Chronometerwerke GmbH was formed in Frankfurt, Germany, to supply the country with high-quality mechanical chronometers and ship clocks for their maritime trade, making the country independent of other international suppliers such as those in England. In 1938 the firm was renamed Wempe Chronometerwerke. The business continues today. Its products now include its well-known chronometers, battery-powered ship clocks, ship’s bell clocks, barometers, barographs, thermometers, hygrometers, comfort meters to measure temperature and humidity, and wristwatches. The company also performs chronometer testing facilities for the State’s Weights and Measures office. The article written by Givi in July 2022 “The Basics of Marine Meteorology – a Guide for Seafarers” refers to the weather’s signs and patterns being repeated over and over, and the recording of these observations helps forecasters predict changes in the weather. The chronometer is an example of a mechanical navigational marine instrument in use in the early to the mid-20th century. The maker is significant as part of a German government initiative to be self-sufficient in the production of good quality marine technology. This chronometer is significant as part of the exhibit, the Australian-built vessel, 1922 coastal trader ‘Reginald M’, listed on the Australian Register of Historic Vessels and on display for over 40 years.Marine chronometer or marine clock, brass case, glass cover, Roman numerals, 24-hour numbers beside them. Two black hands, a keyhole for winding and ventilation holes in the side. The base has a collar with four machined mounting holes. Inscriptions are on the clock’s face."Made in Germany" and "WEMPE / CHRONOMETERWERKE / HAMBURG"flagstaff hill, flagstaff hill maritime museum and village, warrnambool, maritime museum, maritime village, great ocean road, shipwreck coast, marine meteorology, horology, chronometer, marine technology, latitude, marine navigation, mechanical instrument, scientific instrument, ship clock, chromometerwerke gmbh, wempe chronometerwerke, marine clock