Gregorian reflecting telescope, 1748-1788

Gregorian reflecting telescope, 1748-1788

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© The Board of Trustees of the Science Museum

Gregorian telescope with 3-inch speculum mirror, tube stopper and 2 eyepieces by Thomas Short, London in case.

Dated to 1747--68, this reflecting telescope uses the Gregorian optical configuration. First proposed by James Gregory in 1663 it produces upright images. This is a convenience for a telescope that was as likely to be used for terrestrial viewing as for looking for objects in the sky. Made by the London instrument maker, Thomas Short the telescope has a brass tube. The claw-foot tripod stand allows the telescope to be used on a table, while focussing is achieved by moving the tiny mirror at the top of the tube. To aid the finding of objects being observed the telescope is provided with naked-eye viewing sights.

Details

Category:
Astronomy
Object Number:
1928-872
Materials:
brass, speculum and complete
Measurements:
overall: 540 x 500 x 280 mm
type:
telescope - gregorian and telescope - reflecting
credit:
Mr Thomas H. Court

Parts

Gregorian reflecting telescope, 1748-1788

Gregorian reflecting telescope, 1748-1788

Gregorian telescope with 3-inch speculum mirror, tube stopper and 2 eyepieces by Thomas Short, London in case.

More

Dated to 1747--68, this reflecting telescope uses the Gregorian optical configuration. First proposed by James Gregory in 1663 it produces upright images. This is a convenience for a telescope that was as likely to be used for terrestrial viewing as for looking for objects in the sky. Made by the London instrument maker, Thomas Short the telescope has a brass tube. The claw-foot tripod stand allows the telescope to be used on a table, while focussing is achieved by moving the tiny mirror at the top of the tube. To aid the finding of objects being observed the telescope is provided with naked-eye viewing sights.

Materials:
complete , brass (copper, zinc alloy) , speculum (alloy of copper and tin) and glass
Object Number:
1928-872/1
type:
instrument component , telescope - gregorian and telescope - reflecting
Image ©
The Board of Trustees of the Science Museum
Gregorian reflecting telescope, 1748-1788

Gregorian reflecting telescope, 1748-1788

Case for Gregorian telescope with 3-inch speculum mirror, tube stopper and 2 eyepieces by Thomas Short, London.

Materials:
brass , speculum and complete
Object Number:
1928-872/2
type:
component and case
Image ©
The Board of Trustees of the Science Museum