Medium level (H) calcium vapour
- Made:
- 1903 in Lake Geneva
- photographer:
- George Ellery Hale and F Ellerman
Medium level (H) calcium vapour, surrounding the great sun-spot of 1903, October 10, 9h. 39m. C.S.T. slit at 3966.5, suns diam = .77 metre, taken with the Rumford spectroheliograph and 40-inch refractor of the Yerkes Observatory by G.E. Hale and F. Ellerman
