from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A photograph of the sun taken in a narrow wavelength band centered on a selected wavelength.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a photograph taken using a spectroheliograph
from the GNU version of the Collaborative International Dictionary of English
- n. A photograph of the sun made by monochromatic light, usually of the calcium line (k), and showing the sun's faculæ and prominences.
from The Century Dictionary and Cyclopedia
- n. A photograph of the sun made by means of the spectroheliograph with monochromatic light, usually that; of one of the violet calcium lines (K or H), and showing the details of the sun's surface and surroundings as they would appear if no other kind of light were emitted.
spectro- + heliogram (Wiktionary)