The RHESSI Flare Image Archive, located in the flare_images_v2 directory, contains image cube FITS files that can be used with RHESSI image object software, converted to map structures via hsi_fits2map, or read by any standard FITS reader.
The VIS_CS algorithm applies a visibility-based compressed sensing approach to reconstruct solar flare X-ray and gamma-ray images. Instead of working directly with detector count rates, VIS_CS operates on RHESSI’s visibility data, solving an optimization problem that enforces sparsity in the image domain. This method produces high-fidelity images with reduced artifacts and improved dynamic range compared to traditional algorithms, making it particularly effective for complex flare structures.
VIS_CS FITS files follow the naming convention hsi_imagecube_vis_cs_YYYYMMDD_HHMM_xxxxx.fits, where YYYYMMDD and HHMM represent the observation date and start time (UTC), xxxxx indicates the bin size identifier, and .fits denotes the standard Flexible Image Transport System format.