2-foot Gregorian reflecting telescope with split object glass micrometer
Date: circa 1763
Inventory Number: 0002
Classification: Telescope
Subject:
Maker: James Short (1710 - 1768)
Maker: Dollond & Son (1752 - 1761)
Maker: Peter Dollond (1731 - 1820)
User: John Winthrop (1714 - 1779)
User: Samuel Williams (1743 - 1817)
Donor: Nathaniel Sparhawk (1715 - post 1779)
Donor: William Pepperrell Sparhawk (1746 - 1816)
Cultural Region:
Place of Origin:
Dimensions:
with barrel horizontal: 65 x 37 x 100 cm (25 9/16 x 14 9/16 x 39 3/8 in.)
height as shown in photo: 79.5 cm (31 5/16 in.)
Material:
Accessories: split object glass micrometer; spare secondary mirror in tin box (0002b).
Bibliography:
The Apparatus of Science at Harvard, 1765-1800
DescriptionThis brass Gregorian reflecting telescope was the 54th telescope that James Short made with a focal length of 24 inches out of a total 1279 telescopes to date.
The two-foot brass tube has a finder scope mounted at the eye-piece end. The proper left side of the barrel there is a silver plaque engraved with the quartered arms of the Pepperrell and Sparhawk families.
The optical assembly is attached to an altazimuth mount on a pedestal with three folding scroll legs. There are ivory handls on the azimuth and altitude adjustment keys. The altitude key is removable. The adjustment screws for the focusing mechanism and the locking screws have knurled heads.
The primary and secondary mirrors are present. The primary is cracked. A spare secondary mirror is stored in a tin box (see 0002b).
The telescope comes with a split object glass micrometer (also known as a heliometer). It was likely made by John Dollond (I) or Peter Dollond. It is unsigned. The brass frame holds the objective, which is split into two semicircles. A rack and pinion mechanism operates the micrometer by moving the two glasses in opposite directions along a common diameter. The separation is measured on a scale of 0-5.9, with divisions every .05, and a vernier scale of 0-25 gives readings to .01.
There are two brass keys attached to long wooden handles. When fully extended, these are 70.5 cm and 70.8 cm long. The long handles enable the user to adjust the micrometer while his eye is at the eye piece at the other end of the telescope. One causes the split object glasses to move with respect to each other. The other handle and key rotates the micrometer optical system around the axis of the tube.
The two-foot brass tube has a finder scope mounted at the eye-piece end. The proper left side of the barrel there is a silver plaque engraved with the quartered arms of the Pepperrell and Sparhawk families.
The optical assembly is attached to an altazimuth mount on a pedestal with three folding scroll legs. There are ivory handls on the azimuth and altitude adjustment keys. The altitude key is removable. The adjustment screws for the focusing mechanism and the locking screws have knurled heads.
The primary and secondary mirrors are present. The primary is cracked. A spare secondary mirror is stored in a tin box (see 0002b).
The telescope comes with a split object glass micrometer (also known as a heliometer). It was likely made by John Dollond (I) or Peter Dollond. It is unsigned. The brass frame holds the objective, which is split into two semicircles. A rack and pinion mechanism operates the micrometer by moving the two glasses in opposite directions along a common diameter. The separation is measured on a scale of 0-5.9, with divisions every .05, and a vernier scale of 0-25 gives readings to .01.
There are two brass keys attached to long wooden handles. When fully extended, these are 70.5 cm and 70.8 cm long. The long handles enable the user to adjust the micrometer while his eye is at the eye piece at the other end of the telescope. One causes the split object glasses to move with respect to each other. The other handle and key rotates the micrometer optical system around the axis of the tube.
In Collection(s)
Signedat end of telescope barrel: JAMES SHORT LONDON 54 / 1279 = 24.
object glass micrometer: unsigned
object glass micrometer: unsigned
Inscribedon barrel: coat-of-arms of the Pepperell and Sparhawk families.
FunctionThis type of reflector and object glass micrometer was the preferred instrument of observers of the Transit of Venus in 1761 and 1769.
Historical AttributesThis telescope was given to Harvard soon after the fire of 1764 by Nathaniel Sparhawk, acting as guardian for his son, William Pepperrell. Sparhawk had married the daughter of Sir William Pepperrell of Kittery, Maine, and his son inherited his grandfather's estate on the condition that he take his grandfather's name.
Professor Winthrop used this telescope and micrometer to observe the Transit of Venus in 1769 from Cambridge.
In October 1780, Winthrop's successor, Professor Samuel Williams, and several students took the telescope behind enemy lines during the American Revolution in order to observe a total solar eclipse on Long Island in Penobscot Bay, Maine. (He also took another Short reflector, 0053, Ellicott clock, 0070, and most likely the Nairne azimuth compass, 0095, Martin octant, 0007, and Martin surveyor's level, 0068.) The expedition was endorsed by Harvard and the American Academy of Arts and Sciences, and sponsored by the General Court of Massachusetts.
The telescope is mentioned in several archival documents, including an inventory of 1779 that lists "A reflecting Telescope with a micrometer" and "one cannister containing one reflector for the telescope given by Sir William Pepperell." On 18 May 1784, the College treasurer was authorized to send the reflecting telescope to London to be refitted.
Professor Winthrop used this telescope and micrometer to observe the Transit of Venus in 1769 from Cambridge.
In October 1780, Winthrop's successor, Professor Samuel Williams, and several students took the telescope behind enemy lines during the American Revolution in order to observe a total solar eclipse on Long Island in Penobscot Bay, Maine. (He also took another Short reflector, 0053, Ellicott clock, 0070, and most likely the Nairne azimuth compass, 0095, Martin octant, 0007, and Martin surveyor's level, 0068.) The expedition was endorsed by Harvard and the American Academy of Arts and Sciences, and sponsored by the General Court of Massachusetts.
The telescope is mentioned in several archival documents, including an inventory of 1779 that lists "A reflecting Telescope with a micrometer" and "one cannister containing one reflector for the telescope given by Sir William Pepperell." On 18 May 1784, the College treasurer was authorized to send the reflecting telescope to London to be refitted.
Primary SourcesSamuel Williams, "Observations of a solar eclipse, October 27, 1780, made on the east side of Long-Island, in Penobscot-Bay," Memoirs of the American Academy of Arts and Sciences 1 (1785): 86-102.
ProvenanceGift to Harvard, 1764, by Nathaniel Sparhawk, acting as guardian for his son, William Pepperrell (named after his grandfather, Sir William Pepperrell of Kittery, Maine).
Published ReferencesDavid P. Wheatland, The Apparatus of Science at Harvard, 1765-1800 (Cambridge: Harvard University Press, 1968), 20-21.
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. 163.
