I was enamored by the wikipedia article of SN1006. Esp. the fact that it was so bright, it could cast shadows on the ground. (Even this idea that you could have possibly read parchment with just the light from the supernova. Source).
The Question is basically what is the width (radius?) of the remnant as seen in this picture.
You were so close! The answer was actually given lower down on the Wikipedia page: roughly 20 parsecs. Since one parsec is about 3.26 light-years, we can calculate that that comes out to about 64 light-years, as this seems to corroborate. The outer layers of the remnant are expanding outward at an outrageous rate - 11 million miles per hour, according to NASA. I invite you to do the calculations to figure out how large it will be at a certain point in time.
