On a spring night in 1437 AD, something unusual happened — Korean astronomers spotted a new star in the sky above Seoul. It was spotted above Seoul on March 11, 1437, they reported, between the second and third star of a part of the sky that eastern astronomers call the sixth lunar mansion. The star that produced the nova shell is indicated with red tick marks; it is far from the shell's centre today. This series of photographic plates spanning six weeks in 1942 shows the old nova of 1437 A.D. undergoing a dwarf nova eruption. By looking at images over the past century of the star that caused the 1437 nova, Shara spotted the shell thrown off by the eruption and multiple dwarf novas.

Source: CBC News August 30, 2017 17:37 UTC