Calcium and Hydrogen Flocculi (black-and-white prints (photographs); astrophotographs; Sun; sun spots)
Calcium and hydrogen flocculi (black-and-white prints (photographs); astrophotographs; Sun; sun spots)
High level (H2) calcium vapour surrounding the Great Sun-spot of 1903 (black-and-white prints (photographs); astrophotographs; Sun; sun spots)
Medium level (H) calcium vapour (black-and-white prints (photographs); astrophotographs; Sun; sun spots)
Higher (H1) calcium vapour surrounding the great sun-spot of 1903 (black-and-white prints (photographs); astrophotographs; Sun; sun spots)
