Prismatic reflecting half-circle and case

Reflecting half-circle made by Pistor and Martins, Berlin, Germany, about 1860. Brown and yellow-lacquered brass frame, polished limb, a wooden handle. Signed on the limb: PISTOR & MARTINS BERLIN. Marked on the limb: 664. Inlaid silver scale indicating from 350° to 0° to 130° and from 180° to 250°; the entire scale is divided every 10', measuring to 238°. Silver vernier to 10", zero at the centre. The tangent screw and clamping screw (both incomplete) are at the bottom of the index arm. Four half-glass shades (two red, two green), no horizon shades. Index glass without adjustment; adjustment of the horizon prism by capstan screws. Magnifier on a 130-mm swivelling arm, a frosted glass shade. Threaded telescope bracket in two parts, fitted for correcting collimation error by capstan screws; perpendicular adjustment by rising-piece and a milled knob. Telescope (183 mm) inverted image, two cross-wires (broken); telescope (85 mm) erect image; extra draw tube (133 mm) inverted image, two parallel cross-wires. Shaded eyepiece (red). A fitted rectangular mahogany box containing in the lid a trade label for Elliot Brothers, 449 Strand, London (18..-18-..)

Details

Category:
Astronomy
Object Number:
1914-888
type:
reflecting circle
credit:
Mr Thomas H. Court

Parts

Prismatic reflecting instrument by Pistor and Martins

Prismatic reflecting instrument by Pistor and Martins

Prismatic reflecting instrument by Pistor and Martins, Berlin; with 3 telescope eyepieces, cross-wires broken, and suncap, arc 6" radius divided on silver from 15 degrees to 255 degrees.

Object Number:
1914-888/1
type:
navigational instruments and reflecting instruments
Image ©
The Board of Trustees of the Science Museum
Case for prismatic reflecting instrument

Case for prismatic reflecting instrument

Mahogany case with key, for Prismatic reflecting instrument by Pistor and Martins, Berlin; with 3 telescope eyepieces, cross-wires broken, and suncap, arc 6" radius divided on silver from 15 degrees to 255 degrees.

Materials:
mahogany (wood) and silver (metal)
Object Number:
1914-888/2
type:
navigational instruments and reflecting instruments
Image ©
The Board of Trustees of the Science Museum