1-foot Gregorian reflecting telescope
Date: circa 1735
Inventory Number: 0054
Classification: Telescope
Maker: English
Owner: John Winthrop (1714 - 1779)
Cultural Region:
Dimensions:
24.5 x 14.5 x 42.7 cm (9 5/8 x 5 11/16 x 16 13/16 in.)
tube length: 35.4 cm (13 15/16 in.)
Material:
Bibliography:
The Apparatus of Science at Harvard, 1765-1800
DescriptionThis brass Gregorian telescope has a cylindrical barrel formed of two parts screwed together near the mid point. The front end of the tube (the section with the secondary mirror) has two sets of exterior threads--one set on either side of a brass collar--near the screw joint. The back end of the tube (the section with the primary mirror) is of larger diameter than the front end and has internal threads near the screw joint. When stowing the telescope between uses, one can remove the front section, reverse it, and store it inside the rear section of the tube, holding it fast by means of the second set of exterior threads alongside the collar. The other threads are then available to hold on the dust cap.
The focusing knob is mounted on the collar of the secondary half of the tube. The knob is knurled. Primary and secondary mirrors are present.
The tube is covered with brown leather. It is attached to a short pillar ending with a ball. A ball-and-socket joint, with a wing nut for tightening it, holds the telescope in the desired orientation. This socket is attached to a short pedestal, the end of its shaft threaded to mate with the tripod stand. There are three pad feet on curving legs attached to a central turned disk. The legs can fold together.
Inserted into the end of the shaft and extending below the threads is a long conical steel screw to attach the telescope to a tree or post in the field when the legs are removed. The screw is 2.6 cm long.
The focusing knob is mounted on the collar of the secondary half of the tube. The knob is knurled. Primary and secondary mirrors are present.
The tube is covered with brown leather. It is attached to a short pillar ending with a ball. A ball-and-socket joint, with a wing nut for tightening it, holds the telescope in the desired orientation. This socket is attached to a short pedestal, the end of its shaft threaded to mate with the tripod stand. There are three pad feet on curving legs attached to a central turned disk. The legs can fold together.
Inserted into the end of the shaft and extending below the threads is a long conical steel screw to attach the telescope to a tree or post in the field when the legs are removed. The screw is 2.6 cm long.
In Collection(s)
Signedunsigned
Historical AttributesThis telescope belonged to Professor John Winthrop and was used by him for astronomical observations. It survived the fire of 1764. It was given to Harvard at the time of his death in 1779.
Published ReferencesDavid P. Wheatland, The Apparatus of Science at Harvard, 1765-1800 (Cambridge: Harvard University Press, 1968), 15-16.