Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 5 2005 10.5194/acpd-5-10925-2005 http://www.atmos-chem-phys-discuss.net/5/10925/2005/ http://www.atmos-chem-phys-discuss.net/5/10925/2005/acpd-5-10925-2005.html http://www.atmos-chem-phys-discuss.net/5/10925/2005/acpd-5-10925-2005.pdf 10925 10946 2005-10-31 Detection and measurement of total ozone from stellar spectra: Paper 2. Historic data from 1935–1942 R. E. M. Griffin Dept. of Earth and Space Sciences and Engineering, York University, 4700 Keele Street, Toronto, ON, M3J 1P3, Canada Herzberg Institute for Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7, Canada Atmospheric ozone columns are derived from historic stellar spectra observed between 1935 and 1942 at Mount Wilson Observatory, California. Comparisons with contemporary measurements in the Arosa database show a generally close correspondence. The results of the analysis indicate that astronomy's archives command considerable potential for investigating the natural levels of ozone and its variability during the decades prior to anthropogenic interference.