A real light echo

Nova Persei 1901 (GK Per) was first seen in February. In August a surprisingly large nebulosity was discovered around it. This was soon observed to be expanding rapidly. The author illustrates that there is a large outer (broken) ring, an inner and brighter ring, and numerous bright interior features. Many of the features appear to be moving. The outer ring increased its radius at ∼ 11 arcmin year - 1. The presently accepted distance to this nova is D ∼ 400--600 pc, so the apparent projected velocity of expansion was ∼ 4c--6c. The author discusses history of observation and theory of this nebula