The Refraction of the Eye Author: G Hartridge Publisher: J & A Churchill Date: 1919 flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, the refraction of the eye, book

How widely the prisoptometer was used is unclear but the Standard Optical Company later patented a new model, The Standard Prisoptometer, on June 21, 1904. Edward Jackson's crossed cylinder technique of determining astigmatism was first detailed in the Transactions of the American Ophthalmological Society (1887)4:595-598. The convenience of Jackson's crossed cylinder lenses over the prisoptometer in weight, cost, portability and reliability meant that they were soon almost universally adopted.This is a rare item as few are known world wide.This instrument is an optometer, that is, a device to measure the refractive error of an eye. It is made of cast iron, steel, brass and glass. It contains a prism which could be rotated, and was used to view a disc or an object circle. The prism caused monocular doubling of the object circle and the separation of the two images varied as the prism rotated, depending on the astigmatism present. The axis of the astigmatism was indicated by the prisoptometer and trial lenses were used to determine the the magnitude of the spherical and cylindrical refractive errorImprinted:"DR CULBERTSON'S PRISOPTOMETER/ GENEVA OPTICAL COMPANY MAKERS, GENEVA, N.Y./ PATENTED SEPT, 21, 1886". Stamped "853" on eyepiece and lens mounting.optometry, prisoptometer, optometer, astigmatism, refractive error, refraction, culbertson

Trial frames are used to hold trial spectacle lenses in front of the eyes to establish the spectacle refraction. This unit is able to hold 3 lenses in front of each eye. It is very complex for its early date.This trial frame is a rare example of a very complex early design which has survived in good condition. Complex nineteenth century trial frame: double lens clip to front rotated by long control knob. Single downward pointing lens clip to back. Bridge height and extension adjustable. Variable inter-pupillary distance calibrated in inches. Slide extending curl sides. Eye rims stamped:'PAT NOV.6.94 & PAT JUNE25.95'. Sides stamped:'PAT APR.30.95'optometry, eye examination, refraction, trial frame, spectacles

Model eyes were used by students to practise skills of ophthalmoscopy and retinoscopy. This item shows more variety of fundus view and refractive state than most.This fine example is preserved in excellent condition, perhaps through lack of use. It is the most complex of the five model eyes in the collection.Cased metal model eye for teaching ophthalmoscopy and retinoscopy. 17 numbered interchangeable fundi illustrating various pathological conditions. Double cell lens holder in front can hold lenses for retinoscopy. Axis scale on front. 6 lenses provided to simulate various refractive states. Rotating disc changes between 3 pupil sizes. Model eye, fundi samples & lenses enclosed in snap closing wooden case, covered in black leatherette and lined with burgundy velvet.Inside case:'F.DAVIDSON & Co,/ 29 GREAT PORTLAND STREET,/ LONDON, W/ DUNN'S MODEL EYE'optometry, ophthalmology, model eye, teaching, ophthalmoscopy, retinoscopy

This is the 1854 fourth edition of a book on diseases of the eye by William MacKenzie (1791-1868) first published in 1830. William MacKenzie was surgeon oculist in Scotland to Her Majesty (Queen Victoria), lecturer in the University of Glasgow and a surgeon in the Glasgow Eye Infirmary. This fourth edition appeared just after Helmholtz's invention of the ophthalmoscope, but Mackenzie did not at this stage have much understanding of the internal diseases of the eye. Nor did he properly understand refractive errors which were soon to be elucidated by the work of Donders. MacKenzie did however recognise the hardness of the eye as being an essential sign of glaucoma.This book is significant historically as it shows contemporary understanding of eye disease in the early nineteenth century. It is not rare as copies still turn up at book markets and also are held in other Australian institutions.This book, bound in full calf leather (probably later 19th Century) with 1107 pages including an index and is followed by a publisher's catalogue. It is the 1854 fourth edition of William MacKenzie's 'A practical treatise on the diseases of the eye' first published in 1830. It has a long (32 pages) introductory section on the anatomy of the eye by Thomas Wharton Jones, FRS. There are 27 chapters on eye disease. Chapter 24 is on refractive errors and presbyopia.eye, ocular anatomy, ocular disease

This 300 year old book deals with the theory of light and colour and with investigations of the colours of thin sheets, 'Newton's rings', and diffraction of light. Newton uses a wave theory of light and his corpuscular theory to explain his observations. Sir Isaac Newton (1643-1727) was a great figure in the history of optical science. His classic 'Opticks' was first published in English in 1704. This Latin edition of 1706 was published to satisfy a wider scientific audience in Europe. Newton was Lucasian Professor at Cambridge 1669-1693 and a fellow of Trinity College. He achieved fame as a creative mathematician and for his law of universal gravitation which explains planetary motions. He retired from research in 1693 to become a government official in London.This book is highly significant as a milestone in the study of optics. Although not a very rare book, only one other copy is listed by WorldCat in an Australian institution.Latin edition of Newton's 'Optics' translated by Samuel Clarke. This copy is bound in full calf leather of the period, 348 pages, with fold-out figures plus a 24 page appendix 'Enumeratio linearum tertii ordinis' and a 43 page appendix 'Tractus de quadratura curvarum'. It is in outstandingly good condition.Inscribed on the fly leaf in pencil is that this is the 2nd edition, the first in Latin, and that Newton gave Clarke 500 pounds for the translation.refraction, optics, newton, reflection

The period when kerosene was extensively used for indoor lighting was before electrical reticulation was installed in rural areas. In remote areas this was up to the mid 1900's. The kerosene lantern however was still in use, for camping and outdoor activities, well beyond this period and was eventually replaced by LPG and battery powered lighting. The transition phase to "modern" outdoor and domestic lighting lingered on the rural areas where the electrical reticulation suffered from reliable constant supply.In the Kiewa Valley, being a rural region, had reliable electrical domestic and farm supply only after the Kiewa Hydro Electricity Scheme had been fully operational. The supply was relative to how close the homestead was to the major electricity substation. This kerosene lamp was in use during the period when it was the only reliable source of domestic night time lighting. The strength of refractive light produced by this lantern/lamp hinged upon the size of the lamp(wick and glass bowl). The small size of this lamp suggests that it was for use in a small room(children's bedroom) or as providing a light for a safe walk to the outside ablutions (toilet) area. This small kerosene lamp has an enclosed "cup" body which would have contained the kerosene fuel. The top wick holder, made from brass, has an extended enclosed spout which raises the wick approximately 20mm from the bottom of the holder. The wick holder screws into the the top of the kerosene reservoir bowl and has a wick adjustment screw (light control) at one side. The small white glass light reflector bulb nestles securely onto the wick holder and is kept snug by snap designed extending "fingers". The section between the bottom of the refractive glass "light" bowl and the top of the kerosene bowl has perforations to allow air passage to feed directly to the wick.The light refracting bulb is open at the top to allow heat and smoke from the burning wick to escape upwards.On the wick control screw "CWB BRITISH MADE"kerosene reading lamp, domestic lighting, bedside light

This case only includes spherical lenses and has no cylindrical lenses for correction of astigmatism. The lenses have no rims, which was unusual after 1900. The set appears to have had very little use as it is in excellent condition.This is a late example of a trial case comprising only spherical lenses. The trial frame is a very rare type.Small timber cased trial set of spherical lenses only. No rims on lenses. Case labelled with lens powers in dioptres and inches. Trial frame included of unusual design:each eye rim has a sprung top cover to secure lens in place. Nickel alloy. Fixed bridge stamped 62, tapered sides with loop ends. Also a lens handling tool (nickel alloy) to position a lens in front of patient's eye.Lens powers labelled in inches and dioptres. Trial frame bridge stamped '62'.optometry, lenses, refraction, trial case, trial set

Optometrists are trained to examine eyes and prescribe visual aids such as spectacles. The optometer pictured in the media section of this document dates from the 1800s. The optometer was used with various lenses to determine the refraction of the eye. Refraction means the extent to which light is bent by an individual's eye. The result can determine how short-sighted or long-sighted they are, and the strength of spectacles required. In the second half of the 1800s, ophthalmologists also devised instruments to measure the separate components of vision. Dr Jules Badal developed the pictured instrument in 1876. It was based on an optometer invented by William Porterfield in 1759. The brass stands look as though they were made for an optometer to be table mounted, with heavy brass stands and designed to hold a cylindrical object securely as would be required by an optometer. Stands appear to have been very well made and very early probably early to mid 19th Century by a well known scientific instrument maker given there are no inscriptions or marks to indicate the time period made or maker it is difficult to assume significance to these items at this point in time as well as the items are incomplete.The brass stands believed to be for mounting an early Optometer an (ophthalmic instrument) Noneflagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, stands for scientific instrument

Black book of 160 pages. non-fictioncrystals, light, jim thyer, polarizing microscope, refraction, dispersion, absorption spectra

William Baragwanath studied at the Ballarat School of Mines, obtained a Geology certificate in 1911. He was born on 01 August 1878 at Ballarat. He joined the Victorian Department of Mines in 1897 and was Chief Mining Surveyor from 1924 to 1943. Baragwanath died at Prahran on 20 September 1966. See Book 2 - Catalogue Number 4530Marbled card covered exercise book with brown tape spine containing handwritten notes by William Baragwanath on Astronomy and astronomical, geodetic, geights and distances, North Line Latitue, Lime, etc., problems . Headings include: Astronomy refraction Correction for Semi diameter Determination of True Meridian Elongation Observation Latitude Determining the TIme Convergence of Meridian Barometric Measurement of Heights Formulae Latitude Observation On the Division of Land Calculations for Observations by a Single Altitude Computations Triginometrical Rations of Two Arcsballarat school of mines, astronomy, william baragwanath

Group of paper pinned together of various experiments. Items include Tail light invention for Defence Dept. 18/9/41, Heat of glass, Refractive Index Tests on Melbourne Tap Water 31/7/42, Research Data, Manufacture of the Buoys 18/1/43, Specifications 1/12/42, List of substances with their Atomic No., Symbol, Atomic Weight, Melting Point and Year of discovery and a hand drawn diagram for an experiment. Bendigo Electronic Company of Australia Pty Ltdsciences, instruments - general, scalebuoy, bill ashman collection - correspondence, bendigo electronic company of australia pty ltd, defence dept, capt slattery, f a stevenson

A Fresnel lens is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use primarily in lighthouses.  Made from high-quality glass Fresnel lenses were used originally in lighthouses and later for many other applications They were later being used for automobile headlamps, brake, parking, and turn signal lenses, and many other applications. Fresnel lenses used in lighthouses were considered state of the art from the late 19th through to the middle of the 20th century. The subject item is a Fresnel replacement lens used in a ships navigation light. For lighthouses, these lenses have now been replaced with much less expensive and more durable aerobeacons, which themselves often contain plastic Fresnel lenses. The lens design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The catadioptric form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source making the light visible from greater distances.The subject item at this time cannot be associated with a historical event, person or place, provenance is unknown, the item is a replacement for a ships navigation light and it is believed to have been produced before 1950.Fresnel glass replacement lens for a navigation side lamp of a ship. W.T.G (S) and 10x7 S.STR.ENGL.125warrnambool, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, fresnel lens, maritime light, ships navigation light, augustin-jean fresnel, lighthouse lenses, lighthouse, navigation, warning light

A Fresnel lens is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use primarily in lighthouses.  Made from high-quality glass Fresnel lenses were used originally in lighthouses and later for many other applications They were later being used for automobile headlamps, brake, parking, and turn signal lenses, and many other applications. Fresnel lenses used in lighthouses were considered state of the art from the late 19th through to the middle of the 20th century. The subject item is a Fresnel replacement lens used in a ships navigation light. For lighthouses, these lenses have now been replaced with much less expensive and more durable aerobeacons, which themselves often contain plastic Fresnel lenses. The lens design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The catadioptric form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source making the light visible from greater distances.The subject item at this time cannot be associated with a historical event, person or place, provenance is unknown, the item is a replacement for a ships navigation light and it is believed to have been produced before 1950.Fresnel glass replacement lens for a navigation lamp of a ship. None warrnambool, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, fresnel lens, maritime light, ships navigation light, augustin-jean fresnel, lighthouse lenses, lighthouse, navigation, warning light

A Fresnel lens is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use primarily in lighthouses.  Made from high-quality glass Fresnel lenses were used originally in lighthouses and later for many other applications They were later being used for automobile headlamps, brake, parking, and turn signal lenses, and many other applications. Fresnel lenses used in lighthouses were considered state of the art from the late 19th through to the middle of the 20th century. The subject item is a Fresnel replacement lens used in a ships navigation light. For lighthouses, these lenses have now been replaced with much less expensive and more durable aerobeacons, which themselves often contain plastic Fresnel lenses. The lens design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The catadioptric form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source making the light visible from greater distances.The subject item at this time cannot be associated with a historical event, person or place, provenance is unknown, the item is a replacement for a ships navigation light and it is believed to have been produced before 1950.Fresnel glass replacement lens for a navigation mast headlamp of a ship. Nonewarrnambool, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, fresnel lens, maritime light, ships navigation light, augustin-jean fresnel, lighthouse lenses, lighthouse, navigation, warning light

A Fresnel lens is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use primarily in lighthouses.  Made from high-quality glass Fresnel lenses were used originally in lighthouses and later for many other applications They were later being used for automobile headlamps, brake, parking, and turn signal lenses, and many other applications. Fresnel lenses used in lighthouses were considered state of the art from the late 19th through to the middle of the 20th century. The subject item is a Fresnel replacement lens used in a ships navigation light. For lighthouses, these lenses have now been replaced with much less expensive and more durable aerobeacons, which themselves often contain plastic Fresnel lenses. The lens design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The catadioptric form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source making the light visible from greater distances.The subject item at this time cannot be associated with a historical event, person or place, provenance is unknown, the item is a replacement for a ships navigation light and it is believed to have been produced before 1950.Fresnel round glass masthead replacement lens for a navigation lamp of a ship. Nonewarrnambool, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, fresnel lens, maritime light, ships navigation light, augustin-jean fresnel, lighthouse lenses, lighthouse, navigation, warning light

A Fresnel lens is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use primarily in lighthouses.  Made from high-quality glass Fresnel lenses were used originally in lighthouses and later for many other applications They were later being used for automobile headlamps, brake, parking, and turn signal lenses, and many other applications. Fresnel lenses used in lighthouses were considered state of the art from the late 19th through to the middle of the 20th century. The subject item is a Fresnel replacement lens used in a ships navigation light. For lighthouses, these lenses have now been replaced with much less expensive and more durable aerobeacons, which themselves often contain plastic Fresnel lenses. The lens design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The catadioptric form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source making the light visible from greater distances.The subject item at this time cannot be associated with a historical event, person or place, provenance is unknown, the item is a replacement for a ships navigation light and it is believed to have been produced before 1950.Fresnel glass lens for a ships masthead navigation lamp. Nonewarrnambool, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, fresnel lens, maritime light, ships navigation light, augustin-jean fresnel, lighthouse lenses, lighthouse, navigation, warning light

A Fresnel lens is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use primarily in lighthouses.  Made from high-quality glass Fresnel lenses were used originally in lighthouses and later for many other applications They were later being used for automobile headlamps, brake, parking, and turn signal lenses, and many other applications. Fresnel lenses used in lighthouses were considered state of the art from the late 19th through to the middle of the 20th century. The subject item is a Fresnel replacement lens used in a ships navigation light. For lighthouses, these lenses have now been replaced with much less expensive and more durable aerobeacons, which themselves often contain plastic Fresnel lenses. The lens design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The catadioptric form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source making the light visible from greater distances.The subject item at this time cannot be associated with a historical event, person or place, provenance is unknown, the item is a replacement for a ships navigation light and it is believed to have been produced before 1950.Fresnel glass replacement lens for a navigation side lamp of a ship. Nonewarrnambool, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, fresnel lens, maritime light, ships navigation light, augustin-jean fresnel, lighthouse lenses, lighthouse, navigation, warning light

This particular lamp was made for the dinner table or "parlour". This was the most effective indoor lighting before electrical lighting was introduced in the 1940's. These table lights would have still been used after this time as emergency lighting during electrical power shortages (outages). These emergency lighting lamps, including candles, were eventually replaced by battery power. The Kiewa Valley was supplied by electricity well before many other rural regions due to the State Electricity Commission constructing the Kiewa Hydro Electricity power turbines (late 1930's to mid 1950's). Petrol and diesel generators were used in other rural regions before state wide electricity was available.The significance of this kerosene lamp to the Kiewa Valley is that it provides the proof that before the Hydro electricity scheme was established in the valley, householder and commerce relied on candle/kerosene power. Although at certain times before battery and solar energy became the night time lighters the sole source of lighting was candle power and kerosene power. The supply of both however was still required by most of the population by supply from city and larger country town suppliers. This nearly fully glass made table lamp(kerosene) has a large glass bowl/basin like kerosene storage unit with a glass circular finger handle (similar to a ordinary cup). Formed single star like patterns (50mm apart) encircle the centre of the bowl. On top of the bowl sits the metal (brass) wick holder with a small wheel protruding out one side for adjusting the wick length(increasing or decreasing the strength(regulating) of the amount of light projected. Four prongs rise from the circular base light fixture holding the windproof and refractive glass "pot belly" shield. lamp table, kerosene lamp, household lighting (non electrical)

The discovery of the first telescope in 1608 can be attributed to Hans Lippershey of the Netherlands when he discovers that holding two lenses up some distance apart bring objects closer. He applies for a patent on his invention and this becomes the first documented creation of a telescope. Then in 1668, Newton produces the first successful reflecting telescope using a two-inch diameter concave spherical mirror. This opened the door to magnifying objects millions of times far beyond what could ever be obtained with a lens. It wasn’t until 1729 that Chester Moor Hall develops an achromatic lens (two pieces of glass with different indices of light refraction combined produce a lens that can focus colours to almost an exact point resulting in much sharper images but still with some distortion around the edges of the image. Then in 1729 Scottish instrument maker James Short invents the first parabolic and elliptic, distortion-less mirror ideal for reflecting telescopes. We now come to John Dollond who improves upon the achromatic objective lens by placing a concave flint glass lens between two convex crown glass lenses. This had the effect of improving the image considerably. Makers Information: John Dollond (1707-1761) London England he was a maker of optical and astronomical instruments who developed an achromatic (non-colour distorting) refracting telescope and practical heliometer. A telescope that used a divided lens to measure the Sun’s diameter and the angles between celestial bodies. The son of a Huguenot refugees Dollond learned the family trade of silk weaving. He became proficient in optics and astronomy and in 1752 his eldest son, Peter joined his father in an optical business, in 1753 he introduced the heliometer. In the same year, he also took out a patent on his new lenses. He was elected a fellow of the Royal Society in May 1761 but died suddenly in November and his share in the patent passed to his son Peter. In subsequent squabbles between Peter and the many London opticians who challenged his patent, Peter’s consistent position was that, whatever precedents there may have been to his achromatic lenses, his father had independently reached his practical technique on the basis of his theoretical command of Newtonian optics. As a result of maintaining his fathers patent, Dollond s became the leading manufacturer of optical instruments. For a time in the eighteenth and nineteenth century the word 'Dollond' was almost a generic term for telescope rather like 'Hoover; is to vacuum cleaner. Genuine Dollond telescopes were considered to be amongst the best. Peter Dollond (1731-1820) was the business brain behind the company which he founded in Vine Street, Spitalfields in 1750 and in 1752 moved the business to the Strand London. The Dollonds seem to have made both types of telescopes (reflecting and refracting), possessing the technology to produce significant numbers of lenses free of chromatic aberration for refracting telescopes. A Dollond telescope sailed with Captain Cook in 1769 on his voyage to observe the Transit of Venus. Thomas Jefferson and Admiral Lord Nelson were also customers of the Dollonds. Dollond & Co merged with Aitchison & Co in 1927 to form Dollond & Aitchison, the well-known high street chain of opticians, now fully part of Boots Opticians. They no longer manufacture but are exclusively a retail operation.    John Dollond's experiments in optics and how different combinations of lenses refract light and colour gave a better understanding of the divergent properties of lenses. That went on to inform and pave the way for the improvement of our understanding of optics that are represented today. Dollond was referred to in his time as the "Father of practical optics" as a leader in his field he received many prestigious awards. The telescope in the collection is a good example of one of Dollonds early library telescopes and its connection with one of England's 18th-century pioneers in optical development is in itself a significant and an important item to have within the collection. One tube ships day & Night Telescope brass inner tube with timber main tube covered in leather. Unavailable to inspect Inscriptions to determine authenticity.flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, telescope, dolland, shipwreck-coast, flagstaff-hill-maritime-village, royal national life boat institution

This Dollond Day or Nigh telescope was designed to be used in any light conditions, as its name implies. Telescopes are optical instruments designed to make objects appear to be larger or closer. The discovery of the first telescope in 1608 can be attributed to Hans Lippershey of the Netherlands when he discovers that holding two lenses up some distance apart bring objects closer. He applies for a patent on his invention and this becomes the first documented creation of a telescope. Then in 1668, Newton produces the first successful reflecting telescope using a two-inch diameter concave spherical mirror. This opened the door to magnifying objects millions of times far beyond what could ever be obtained with a lens. It wasn’t until 1729 that Chester Moor Hall develops an achromatic lens (two pieces of glass with different indices of light refraction combined produce a lens that can focus colours to almost an exact point resulting in much sharper images but still with some distortion around the edges of the image. Then in 1729 Scottish instrument maker James Short invents the first parabolic and elliptic, distortion-less mirror ideal for reflecting telescopes. We now come to John Dollond who improves upon the achromatic objective lens by placing a concave flint glass lens between two convex crown glass lenses. This had the effect of improving the image considerably. Makers Information: John Dollond (1707-1761) London England he was a maker of optical and astronomical instruments who developed an achromatic (non-colour distorting) refracting telescope and practical heliometer. A telescope that used a divided lens to measure the Sun’s diameter and the angles between celestial bodies. The son of a Huguenot refugees Dollond learned the family trade of silk weaving. He became proficient in optics and astronomy and in 1752 his eldest son, Peter joined his father in an optical business, in 1753 he introduced the heliometer. In the same year, he also took out a patent on his new lenses. He was elected a fellow of the Royal Society in May 1761 but died suddenly in November and his share in the patent passed to his son Peter. In subsequent squabbles between Peter and the many London opticians who challenged his patent, Peter’s consistent position was that, whatever precedents there may have been to his achromatic lenses, his father had independently reached his practical technique on the basis of his theoretical command of Newtonian optics. As a result of maintaining his fathers patent, Dollond s became the leading manufacturer of optical instruments. For a time in the eighteenth and nineteenth century the word 'Dollond' was almost a generic term for telescope rather like 'Hoover; is to vacuum cleaner. Genuine Dollond telescopes were considered to be amongst the best. Peter Dollond (1731-1820) was the business brain behind the company which he founded in Vine Street, Spitalfields in 1750 and in 1752 moved the business to the Strand London. The Dollonds seem to have made both types of telescopes (reflecting and refracting), possessing the technology to produce significant numbers of lenses free of chromatic aberration for refracting telescopes. A Dollond telescope sailed with Captain Cook in 1769 on his voyage to observe the Transit of Venus. Thomas Jefferson and Admiral Lord Nelson were also customers of the Dollonds. Dollond & Co merged with Aitchison & Co in 1927 to form Dollond & Aitchison, the well-known high street chain of opticians, now fully part of Boots Opticians. They no longer manufacture but are exclusively a retail operation.    John Dollond's experiments in optics and how different combinations of lenses refract light and colour gave a better understanding of the divergent properties of lenses. That went on to inform and pave the way for the improvement of our understanding of optics that is represented today. Dollond was referred to in his time as the "Father of practical optics" as a leader in his field he received many prestigious awards. The telescope in the collection is a good example of one of Dollond's early library telescopes. Its connection with one of England's 18th century pioneers in optical development makes it a significant and an important item to have within the collection.Telescope: Dollond's Telescope, Day or Night model navigational instrument. Telescope is mounted on wooden tripod stand that has folding legs. Brass telescope with leather sheath over barrel, adjustable angle fitting with brass wing nuts that join the legs to the top frame, which is then joined to the telescope pole by an adjustable screw fitting. Manufactured by Dollond, London. Inscription reads "Dollond London, Day or Night" and "DOLLOND LONDON"flagstaff hill, warrnambool, shipwrecked-coast, flagstaff-hill, flagstaff-hill-maritime-museum, maritime-museum, shipwreck-coast, flagstaff-hill-maritime-village, telescope, dollond, dollond london, day & night telescope, floor-standing telescope, optical instrument, john dollond, peter dollond, achromatic telescope, heliometer, light refraction, instrument maker, lens, transit of venus, astronomical telescope, concave lens, library telescope, dollond telescope, day or night, day or night telexcope, scientific instrument, navigation, navigational instrument, astronomy

Blue hard covered book with gold writing and illustrations on front cover, illustrations, 196 pages. Targetted to the general reader of the scientific principles of heat, light and sound topics include heat; light (including reflection and refraction); vision (including vision and optical illusions, the eye, chromatic aberration, spinning tops); optical illusions (including occular estimation, zollner's designs, the thaumatrope, phenakistoscope, zootrope, praxinoscope, the dazzling top); optical illusions cont. (including the talking head, ghost illusions); optical apparatus (including the eye, the streoscope, spectrum analysis, the spectroscope, the telescope and microscope, photography, dissolving views, luminous paint); spectral illusions (including a spectre, ghosts); acoustics (including the harmonograph); acoustics cont (including the topophone, the megaphone, the autophone, the audiphone, the telephone, the phonograph, the microphone). non-fictionscience, science class, scientific recreation series, light, heat, sound, ballarat ironworkers & polytechnic association

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. 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. Unidentified survey operations base, L to R: unidentified personnel. .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