
%0 Journal Article
%A Le Marne, AE 
%T Observations of 23 Planetary Nebulae at 408 MHz
%J Australian Journal of Physics
%D 1969/08/01
%V 22
%N 4
%P 545-548
%K 
%R https://doi.org/10.1071/PH690545
%U https://www.publish.csiro.au/paper/PH690545 
%X Various observers (e.g. Slee and Orchiston 1965; Davies et al. 1967; Hughes 1967; Thompson and Colvin 1967; Thompson, Colvin, and Stanley 1967; Kaftan-Kassim 1968) have so far detected nearly 100 planetary nebulae a.t high radiofrequencies (~3 GHz). In this range, the nebulae have been shown to be optically thin, their spectra being almost flat. Wherever possible, the radio flux densities have been compared with hydrogen recombination line observations. 
