Absolute spectrophotometry of Neptune - 3390 to 7800 A

Comparisons are undertaken of the results of Neptune absolute spectrophotometry from 3390 to 7800 A (having 10-A resolution over 3390-6055 A and 20-A resolution over 6055-7800 A) with both filter photometry and synthetic spectra computed on the basis of a parameterization proposed by Podolak and Danielson (1977) for aerosol scattering and absorption. A CH4/O2 ratio of between 0.01 and 0.1 is derived for the convectively mixed portion of the Neptune atmosphere, which constrains the optical properties of hypothetical aerosol layers.