Plane Rowland diffraction grating on speculum metal
- Made:
- 1895-1909 (estimated) in Baltimore and Allegheny City
- maker:
- Henry Augustus Rowland
Plane Rowland diffraction grating on speculum metal, grating area 45 x 35 mm, with scratched markings reading 'Plate prepared at the Astronom / ical and Physical Instrument / Works of J A Brashear / Allegheny Pa USA', 'Ruled on Rowlands Engine / Johns Hopkins Univty / Baltimore Md / USA', 'AE... / 1896' and '14438 lines to one inch / 568 to one m/m', in blackened metal stand with removable glass cover and three adjustable feet.
Details
- Category:
- Optics
- Object Number:
- 2000-1444
- Materials:
- speculum metal, metal and glass
- Measurements:
-
stand, overall: 72 x 115 x 102 mm
diameter: 60mm
- credit:
- Imperial College of Science,Technology & Medicine (Spectroscopy Group)