RHESSI Observation of an Occulted Hard X-ray Flare

We present an observation of an occulted GOES C2 class flare which occurred on 13 May 2002 10:50-22:20 UT taken by the recently launched Reuven Ramaty Solar Spectroscopic Imager mission (RHESSI) in open-shutter mode. The flare is inferred to originate 34 degrees behind the east limb by tracking the most probable originating active region (NOAA Active Region 9957). This relatively large occultation could explain why no impulsive flare phase was observed. The hard X-ray (8-15 keV) source centroid position as a function of time initially shows a constant position just above the solar limb for approximately 2 hours. Then the source appears to rise above the limb, in a manner that could not be due solely to solar rotation. RHESSI CLEANed images at 7" resolution demonstrate coronal source motion as a function of time. Presently we are investigating spectra with resolution down to 1 keV and energy coverage down to 3 keV and the derived temperature and emission measure. A limb flare observed on 21 April 2002 00:30-04:00 UT is presented as a comparison.