Object Details
- Dollond
- Description
- This telescope has an achromatic objective of 2.75 inches aperture, brass tube with finder, several eyepieces, two telescoping braces, two control rods, a split objective micrometer, equatorial mount, and wooden tripod. The tube is 43.5 inches long. The faceplate at the eye end is marked “DOLLOND * LONDON.” For storage, the telescope fits into a mahogany box with a hinged lid.
- This seems to be an example of the brass telescope “of 3½ feet focal length, with an aperture of 2¾ inches, two eye tubes for Land Objects, and two tubes for Astronomical purposes” that George Dollond was offering in the 1830s. That instrument could be had with either a brass stand for use on a table, or “a mahogany folding stand, to be used on the Floor.” It could, moreover, be “supported in the centre of Gravity, and applied to a socket that may be turned to any latitude, so that the Telescope may have an Equatorial Motion” The complete outfit cost £50. The micrometer would be extra.
- The Dollond family began working as opticians in London in 1750, and gained fame in 1758 when John Dollond introduced his design for achromatic lenses. John Dollond was also responsible for the split objective micrometer.
- Ref: “A Description of a Contrivance for Measuring Small Angles, by Mr. John Dollond; Communicated by Mr. J. Short, F.R.S.,” Philosophical Transactions of the Royal Society of London 48 (1753): 178-181.
- “An Explanation of an Instrument for measuring small Angles, the first Account of which was read before the Royal Society May 10, 1753. By Mr. John Dollond,” Philosophical Transactions of the Royal Society of London 48 (1754): 551-564.
- George Dollond, A Catalogue of Optical, Mathematical, Philosophical Instruments (London, ca. 1830).
- Gloria Clifton, “Dollond Family,” in Oxford Dictionary of National Biography.
- Location
- Currently not on view
- probably 1760s
- probably 1830s
- ID Number
- 1979.1110.01
- accession number
- 1979.1110
- catalog number
- 1979.1110.01
- Object Name
- telescope, refracting
- Physical Description
- brass (overall material)
- wood (overall material)
- Measurements
- overall: 13.5 cm x 23 cm x 116 cm; 5 5/16 in x 9 1/16 in x 45 21/32 in
- overall in case: 5 1/2 in x 9 in x 46 in; 13.97 cm x 22.86 cm x 116.84 cm
- place made
- United Kingdom: England, London
- See more items in
- Medicine and Science: Physical Sciences
- Science & Mathematics
- National Museum of American History
- Subject
- Astronomy
- Record ID
- nmah_1183758
- GUID (Link to Original Record)
- https://n2t.net/ark:/65665/ng49ca746aa-3d17-704b-e053-15f76fa0b4fa
