Calibrated HI Lyman alpha observations with TRACE

Since shortly after launch in April 1998, the Transition Region and Coronal Explorer (TRACE) observatory has amassed a collection of H I L alpha (1216 Angstrom) observations of the Sun that have been not only of high spatial and temporal resolution, but also span a duration in time never before achi eved. The L alpha images produced by TRACE are, however, composed of not on ly the desired line emission, but also local ultraviolet continuum and long er wavelength contamination. This contamination has frustrated attempts to interpret TRACE observations in H I L alpha. The Very Advanced Ultraviolet Telescope (VAULT) sounding rocket payload was launched from White Sands Mis sile range 7 May 1999 at 20:00 UT. The VAULT telescope for this flight was a dedicated H I L alpha imaging spectroheliograph. We use TRACE observation s in the 1216 Angstrom and 1600 Angstrom channels along with observations f rom the VAULT flight to develop a method for removing UV continuum and long er wavelength contamination from TRACE L alpha images.