SIMBAD references

``One man's noise is another man's signal.'' Never has that (mis)quotation been more apt than in this instance, in which the annoying features of telluric origin, bypassed and avoided by the astronomer, need to be salvaged by the atmospheric scientist from data detritus. This paper describes the first phase of a project designed to determine telluric O₃ column densities from historic stellar spectra, and demonstrates the validity of the concept by comparing the results with almost contemporary measurements made by satellite.