“…Using the solar image as a source along with precise pointing knowledge permits a reliable, consistent, and accurate long-term measurement of important species. For example, the Stratospheric Aerosol and Gas Experiment II (SAGE-II) (McCormick et al, 1989), monitored density, ozone, water, and aerosol for over 21 yr, and the Halogen Occultation Experiment (HALOE) (Russell et al, 1993), monitored these along with several halogen species and temperature as a function of pressure, T (P ), for over 14 yr. More recently, the Solar Occultation For Ice Experiment (SOFIE) (Gordley et al, 2009b), has achieved remarkable measurements of polar…”