an image of the sun obtained by a spectroheliograph, which shows light of a particular wavelength, such as calcium or hydrogen, and the distribution of the element over the surface and in the solar atmosphere
spectroheliogram in American English
(ˌspɛktrəˈhiliəˌgræm)
US
noun
a monochromatic image of the sun's chromosphere produced by a spectroheliograph