Flagstaff Hill Maritime Museum and Village
Instrument - Telescope, Early 18th Century
... that has folding legs. Brass telescope with leather sheath over... flagstaff-hill-maritime-village telescope dollond dollond london day ...
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
Flagstaff Hill Maritime Museum and Village
Flagstaff Hill Maritime Museum and Village
Flagstaff Hill Maritime Museum and Village
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