Concave Rowland-type diffraction grating on speculum metal

Made:
1882-1909 (estimated) in Baltimore and Allegheny City
maker:
Henry Augustus Rowland
Concave Rowland-type diffraction grating on speculum metal

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Concave Rowland-type diffraction grating on speculum metal
Science Museum Group
© The Board of Trustees of the Science Museum

Concave Rowland-type diffraction grating on speculum metal, grating area 130 x 75 mm, with bevelled glass cover plate in heavy aluminium case. Unsigned, but similar gratings made by Brashear and Rowland. Typescript label reads '15,000 lines per inch, / right extreme 1½" defective'.

Details

Category:
Optics
Object Number:
2000-1446
Materials:
speculum metal and metal, cast
Measurements:
grating block: 19 x 160 x 133 mm
metal case, overall: 52 x 200 x 185 mm
type:
diffraction grating - reflection
credit:
Imperial College of Science,Technology & Medicine (Spectroscopy Group)