Fig3_7 Spectroheliograph

Fig3_7 Spectroheliograph

Fig. 3.7 . A small section of the Sunís image at the focal plane of a telescope is selected with a narrow entry slit, S1, and this light passes to a diffraction grating to produce 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 solar 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