overall: 11 1/8 in x 35 1/4 in; 28.2575 cm x 89.535 cm
Object Name:
spectrum photograph
Place made:
United States: Maryland, Baltimore
Date made:
1886
Description:
“PHOTOGRAPHIC MAP OF THE SOLAR SPECTRUM / MADE BY PROF. H. A. ROWLAND, JOHNS HOPKINS UNIVERSITY.” This is from the first series, and extends from 40.8 to 45.3 units.
Henry A. Rowland, the first professor of physics at Johns Hopkins University in Baltimore, Md., produced a photographic map of the solar spectrum using concave diffraction gratings made with his own ruling engine. The first edition, published in 1886, covered the region from wave-length 3100 to 5790. The scale of these maps was much greater than the maps of Angstrom or Rutherfurd, and they showed many more spectral lines.
Ref: “Photograph of the Normal Solar Spectrum. Made by Professor H. A. Rowland,” <i>Johns Hopkins University Circular</i> 5 (1886).
