Concave Rowland diffraction grating on speculum metal
- Made:
- 1899 in Baltimore and Allegheny City
- maker:
- Henry Augustus Rowland
Concave Rowland diffraction grating on speculum metal, grating area 84 x 41 mm, with scratched markings reading 'Plate prepared at the Astronomical / & Physical Instrument Works of / J A Brashear Allegheny, Pa USA / 1899' and 'Ruled on Rowlands Engine / Johns Hopkins University Baltimore Md 1899 / Rad = 10 ft', other markings illegible, in wooden cradle in wooden case.
Details
- Category:
- Optics
- Object Number:
- 2000-1445
- Materials:
- speculum metal, wood and brass
- Measurements:
-
grating block: 14 x 102 x 100 mm
case, overall: 108 x 137 x 150 mm
- credit:
- Imperial College of Science,Technology & Medicine (Spectroscopy Group)