The Collaborative International Dictionary
Spectroheliograph \Spec`tro*he"li*o*graph\, n. (Astrophysics) An apparatus for making spectroheliograms, consisting of a spectroscopic camera used in combination with a telescope, and provided with clockwork for moving the sun's image across the slit. -- Spec`tro*he`li*o*graph"ic, a.
Wiktionary
n. (context astronomy English) an instrument that produced monochromatic photographs of the sun using light at a selected wavelength
Wikipedia
The spectroheliograph is an instrument used in astronomy which captures a photographic image of the Sun at a single wavelength of light, a monochromatic image. The wavelength is usually chosen to coincide with an spectral wavelength of one of the chemical elements present in the Sun.
It was developed independently by George Ellery Hale and Henri-Alexandre Deslandres in the 1890s and further refined in 1932 by Robert R. McMath to take motion pictures.
The instrument comprises a prism or diffraction grating and a narrow slit that passes a single wavelength (a monochromator). The light is focused onto a photographic medium and the slit is moved across the disk of the Sun to form a complete image.
It is now possible to make a filter that transmits a narrow band of wavelengths which produces a similar image, but spectroheliographs remain in use.
Usage examples of "spectroheliograph".
Soon her monitors showed that data was starting to come in on hydrogen alpha emission, ultraviolet line spectra, ultraviolet and X-ray imaging, spectrography of the active regions, zodiacal light, spectroheliographs.
Photographed with the spectroheliograph, using the light emitted by glowing calcium vapor.
Made with the spectroheliograph, showing the immense vortices, or whirling storms like tornadoes, that centre in sun-spots.
At the front was her small pressurized hab compartment, and there were two pallets at the rear fitted with a bunch of instruments that would be deployed at the neutron star: coronagraphs, spectroheliographs, spectrographic telescopes.
There was a scheme to observe major solar events like spots and flares from the two widely separate vantage points of Ares and Earth, and so there was a whole bunch of instruments which would be directed at the sun: a coronagraph, a spectroheliograph, a spectrographic telescope.