Source : Webster's Revised Unabridged Dictionary (1913)

Spectroheliogram \Spec`tro*he"li*o*gram`\, n. [Spectrum + heloi-
   + -gram.] (Astrophysics)
   A photograph of the sun made by monochromatic light, usually
   of the calcium line (k), and showing the sun's facul[ae] and
   prominences.