Refracting telescope on equatorial stand, 1749-1783

Baker refracting telescope of 1 3/16- inch aperture and 18 inch focal length by J. Sisson, London, on an adjustable equatorial mounting with a flat base stand and wooden case [RAS No.20]. Presented to the Royal Astronomical Society around 1869 by Baker?

Dated to the middle of the seventeenth century, this small brass telescope was made in London by either Jonathan Sissons or his son, Jeremiah. The instrument has a 1¼-inch lens and is carried on an equatorial mount of the type first introduced by the Sissons. Used in conjunction with a table, the equatorial stand was made horizontal using the three adjusting screws and the pair of spirit levels. Once adjusted, objects could be located using the circular setting scales and the naked-eye sight that is folded down in the photograph. A telescope this quality would have only been affordable to wealthy individual who had an interest in astronomy.

Details

Category:
Astronomy
Object Number:
1931-349
Materials:
brass and optics, glass
type:
telescope - refracting and equatorial instrument
credit:
Royal Astronomical Society

Parts

Case for Baker refracting telescope of 1 3/16 inch aperture and 18 inch focal length by J. Sisson

Case for Baker refracting telescope of 1 3/16 inch aperture and 18 inch focal length by J. Sisson

Case for Baker refracting telescope of 1 3/16 inch aperture and 18 inch focal length by J. Sisson, London.

Materials:
wood
Object Number:
1931-349 Pt1
type:
components , storage boxes and instruments
Image ©
The Board of Trustees of the Science Museum
Baker refracting telescope of 1 3/16- inch aperture and 18 inch focal length by J. Sisson

Baker refracting telescope of 1 3/16- inch aperture and 18 inch focal length by J. Sisson

Baker refracting telescope of 1 3/16- inch aperture and 18 inch focal length by J. Sisson, London, on an adjustable equatorial mounting with a flat base stand [RAS No.20]. Presented to the Royal Astronomical Society around 1869 by Baker?