Observations are presented of the fluxes (in energy units) in the Hp and [0 iii] N1 and N2 lines from fifteen planetary nebulae. The calibration is provided by measurements of bright stars with continuous spectra previously measured by Code, while the conversion into energy units is provided by the solar constant and the sun's visual magnitude. Some of the planetaries were previously measured by Liller and Aller, and the agreement between the two sets of results is good. The ratio of strength of the green lines is F(N1)/F(N2) = 3.05. The two small planetaries that are brightest in Hp and hence most suitable for detection as radio-frequency thermal sources are NGC 6543 and IC 418.