On the Balmer - Paschen ratio in prominences

Vidicon data for the intensities of Balmer and Paschen lines for n = 11 to 18 indicate a line ratio within 1sigma of the theoretical value of 3.27, calculated with the assumptions of an optically thin atmosphere and angular momentum substates populated according to their statistical weights. The observed value is not consistent with the value of 8 reported in some early work, or with the model that higher angular momentum states have low populations. (orig.)