Fig. 2


Download original image

Examples of spectral line types summarized by Mitchell. Type 4 corresponds to a widened line, types 5–6 are widened lines with the centers reversed bright, and type 7 is widened and weakened line. Grey horizontal band corresponds to sunspot location on a spectrograph slit. Adopted from Report of Committee on Sun-Spot Spectra (1908).

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.