THE NUMBER OF SNRS OLDER THAN 10 000 YR WELL STUDIEDIN X RAYS IS SMALL DUE TO THE OBSERVATIONALDIFFICULTIES OF MAPPING LOW SURFACE BRIGHTNESS THERMALPLASMAS WITH TEMPERATURES OF A FEW TENTHS OF A KEVWITH INTERSTELLAR ABSORPTION. WE PROPOSE TO OBSERVETHE BRIGHT LIMB OF G296.5 10.0 ALSO KNOWN AS PKS1209-51 52 WITH THE EPIC INSTRUMENTS. WE WILL PRODUCEA MAP OF THE BRIGHT SOFT THERMAL EMISSION ALONGTHE SOUTHEASTERN SHELL TO BE COMPARED WITH OPTICAL RADIO AND CO CONTINUUM MAPS. WE WILL CHARACTERIZETHE TEMPERATURE AND DENSITY VARIATIONS IN THE SHELL WHICH RESULT FROM INTERACTIONS BETWEEN THE FORWARDSHOCK AND STRUCTURES IN THE ISM. A MORE COMPLETEUNDERSTANDING OF THE OLD VERY LARGE SNRS WILL HELPUS UNDERSTAND THE FEEDBACK ROLE THAT SNE PLAY IN THEEVOLUTION OF THE GALACTIC ISM.