Abstract: A combination of published and archival observations from the Smithsonian Institution's Astrophysical Observatory (APO) is presented and analyzed. This paper concentrates on the data from the two primary sites?Mount ...

Abstract: Baseline total atmospheric ozone values have been derived, using the Chappuis band, from historical data for 11 Smithsonian sites, including both Northern and Southern Hemispheres. The main baselines consist of 1194 and ...

Abstract: Analysis is made of atmospheric transmission measurements taken during the first half of the twentieth century at thirteen widely separated sites by the Astrophysical Observatory of the Smithsonian Institution. Long and ...