Short, James, 1752 c.+4
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Photo

photo - eyepiece
Basic Info

Maker: Short, James

Year: 1752 c.+4

Year Range: -

Year Notes:

Manufacturing Location: London, England

Signature:

Signature Notes:

Inscriptions:

No stand present.

Collection: National Maritime Museum

Accession #: AST0942

Sources:

Royal Museums Greenwich. "Portable reflector telescope". http://collections.rmg.co.uk/collections/objects/11104.html. [Accessed: June 2016].

Public Notes:

"This is a portable Gregorian (reflecting) telescope. It is signed JAMES SHORT LONDON 128/832 = 12 meaning it has a focal length of 12 inches (304.8mm), and that James Short had made 128 of that size out of a total 832 telescopes by the time he made this one. The barrel is made of brass. It has adjustable inclination and rotary movement (or altitude and azimuth movement). The eyepiece has a brass cap and there is a brass cap at the object end. Within the barrel are primary and secondary specula (mirrors). There is a screw thread for focusing by moving the secondary mirror by use of the rod attached to the barrel. There is no finderscope but a sighting sytem instead. The telescope is in good condition. The length with the eyepiece is 525 mm, the diameter of the barrel is 85 mm, and the focal length is 304.8mm (12 inches). The telescope is mounted on a pillar stand with three folding claw legs"

Length (open): 525

Length (closed):

F-ratio:

Exit pupil:

Object status:

Optical Basics

Objective type: gregorian

Optical style gregorian

Physical style

Functional style

Materials: brass, speculum, mahogany

Optical/Lab Data

Drawtube data:

Drawtube notes:

Objective Data

Eyepieces

Notes:

WavelengthParaxial70%Whole
652 ± 6.1 ± 0.14 ± ±
575 ± 0 ± ±
482 ± -11.5 ± 0.9 ± ±