Spectroheliograph

Spectroheliograph

. A small section of the image at the focal plane of a telescope is selected with a narrow entry slit, S1, and light passes to a diffraction grating, producing a spectrum. A second slit, S2, at the focal plane selects a specific wavelength from the spectrum. If the plate containing the two slits is moved horizontally, then the entrance slit passes adjacent strips of the image. The light leaving the moving exit slit then builds up an image of the Sun at a specific wavelength.

Copyright 2010, Professor Kenneth R. Lang, Tufts University