title: High precision refraction measurements by solar imaging during occultation: results from SOFIE.
abstract: A new method for measuring atmospheric refraction angles is presented, with in-orbit measurements demonstrating a precision of +/-0.02 arcsec (+/-0.1 microrad). Key advantages of the method are the following: (1) Simultaneous observation of two celestial points during occultation (i.e., top and bottom edges of the solar image) eliminates error from instrument attitude uncertainty. (2) The refraction angle is primarily a normalized difference measurement, causing only scale error, not absolute error. (3) A large number of detector pixels are used in the edge location by fitting to a known edge shape. The resulting refraction angle measurements allow temperature sounding up to the lower mesosphere.
authors.affiliation: GATS, Incorporated, 11864 Canon Boulevard, Suite 101, Newport News, Virginia 23606, USA. l.l.gordley@gats-inc.com
authors.forename: Larry
authors.initials: L
authors.lastname: Gordley
authors.forename: John
authors.initials: J
authors.lastname: Burton
authors.forename: Benjamin T
authors.initials: BT
authors.lastname: Marshall
authors.forename: Martin
authors.initials: M
authors.lastname: McHugh
authors.forename: Lance
authors.initials: L
authors.lastname: Deaver
authors.forename: Joel
authors.initials: J
authors.lastname: Nelsen
authors.forename: James M
authors.initials: JM
authors.lastname: Russell
authors.forename: Scott
authors.initials: S
authors.lastname: Bailey