1998A&A...339..183R

We present a model for the integrated flux density of W3(OH) and K3-50A allowing these sources to be used as reliable secondary calibrators between 80 and 800GHz. Using new narrow-band continuum measurements between 86-245GHz with the 30m telescope and reasonable assumptions about the source sizes, we construct continuum spectra from the mm-to-submm range which are in very good agreement with previously published data. With the fit parameters given in this paper, observers at any single-dish telescope will be able to calculate the expected flux densities of the two sources at any given aperture and frequency.