spare primary mirror for Gregorian telescope
Date: circa 1767
Inventory Number: 0001d
Classification: Mirror
Maker: James Short (1710 - 1768)
Supplier: Benjamin Franklin (1706 - 1790)
User: John Winthrop (1714 - 1779)
Repaired by: W. & S. Jones (fl. 1791 - 1859)
Cultural Region:
Place of Origin:
Dimensions:
mirror: 17.3 × 17.3 × 1.6 cm (6 13/16 × 6 13/16 × 5/8 in.)
case: 20 × 19.5 × 4.5 cm (7 7/8 × 7 11/16 × 1 3/4 in.)
Material:
Bibliography:
The Apparatus of Science at Harvard, 1765-1800
Description:
This is a spare primary mirror of speculum metal for a Gregorian telescope. It is held in a circular wooden case painted black. The rim is chipped. The mirror is alleged to belong to the four-foot long Short reflector (0001a), but may in fact belong to another telescope.
In Collection(s)
Signedunsigned
Historical AttributesThis large brass Gregorian telescope has a four-foot focus. The end of the barrel is engraved 9 = 48, indicating that it was only the ninth telescope with this focal length made by James Short, who died before the mirror could be mounted.
The telescope was acquired with the help of Benjamin Franklin, who visited Short's workshop to supervise the progress of the construction. Franklin told Winthrop by letter (2 July 1767) that Short had "finished the material parts that required his own hand" before he died, but the telescope needed "something about the mounting, that was to have been done by another workman." Thomas Short, James's brother, saw to the completion of the instrument. The bill for the remarkable instrument was 100 guineas.
Winthrop kept this telescope at his house, and used it for the Transit of Venus in 1769.
Repairs were necessary by the early 19th century, and these were undertaken in London by W. & S. Jones. They left the primary mirror untouched, explaining that "the figure is very good like all of James Short's." They did supply "a new stand upon an improved principle in brass, with mahogany folding legs, graduated circle and arch, etc., etc.; cleaning and repairing the brass work of the tube, finder, eye piece, etc.; new japaning the tube, cleaning and adjusting speculums of a Short's 5 [sic] feet Reflector 7 inches aperture, with deal case for eye pieces and speculums." They charged £54.12.0.
The College protested. So, on 19 August 1817, William Jones made this case: "Short's telescope was charged originally [at] more than 100 guineas, [yet] his stand was unmechanical or ill contrived....[The new stand] is very material and [a] most expensive part of the instrument, and we are confident in declaring the value of the Telescope at present is 150 pounds, whereas in the state sent to us for practical & steady use, an Astronomer would not have given 50 shillings. The price of our 4 feet, so mounted is 100 guineas."
The telescope was acquired with the help of Benjamin Franklin, who visited Short's workshop to supervise the progress of the construction. Franklin told Winthrop by letter (2 July 1767) that Short had "finished the material parts that required his own hand" before he died, but the telescope needed "something about the mounting, that was to have been done by another workman." Thomas Short, James's brother, saw to the completion of the instrument. The bill for the remarkable instrument was 100 guineas.
Winthrop kept this telescope at his house, and used it for the Transit of Venus in 1769.
Repairs were necessary by the early 19th century, and these were undertaken in London by W. & S. Jones. They left the primary mirror untouched, explaining that "the figure is very good like all of James Short's." They did supply "a new stand upon an improved principle in brass, with mahogany folding legs, graduated circle and arch, etc., etc.; cleaning and repairing the brass work of the tube, finder, eye piece, etc.; new japaning the tube, cleaning and adjusting speculums of a Short's 5 [sic] feet Reflector 7 inches aperture, with deal case for eye pieces and speculums." They charged £54.12.0.
The College protested. So, on 19 August 1817, William Jones made this case: "Short's telescope was charged originally [at] more than 100 guineas, [yet] his stand was unmechanical or ill contrived....[The new stand] is very material and [a] most expensive part of the instrument, and we are confident in declaring the value of the Telescope at present is 150 pounds, whereas in the state sent to us for practical & steady use, an Astronomer would not have given 50 shillings. The price of our 4 feet, so mounted is 100 guineas."
Curatorial RemarksTag: "speculum mirror and case. # 1 & 2" from Short-Jones telescope; 49" focus
Published ReferencesDavid P. Wheatland, The Apparatus of Science at Harvard, 1765-1800 (Cambridge: Harvard University Press, 1968), 17-19.
Rolf Willach, "List of Extant Reflecting Telescopes Made by James Short," i>Journal of the Antique Telescope Society, no. 29 (Fall 2007): 11-22, no. 186.
