I live in Ottawa, Ontario, Canada. I captured the almost exact same image of this giant silkworm on my cell phone on May 25, 2010.
In the fall 2009 I found a large, light brown cocoon clinging to a piece of fencing that my neighbor had put out for garbage collection. I rescued it along with its piece of fencing and during the winter months I placed it in a sunny and protected area behind our garage. We had an early snow melt so in early March 2010 I moved it to the front garden behind an evergreen bush right up the the side of the house but protected from direct sunlight and any hungry returning birds. In late May I was rewarded one morning to see that this beautiful creature had completed its metamorphosis and was resting on the stucco siding of the house drying its wings. There it stayed, moving its wings slightly to different positions throughout the entire day. It was gone the next morning.
In my 25 years living in Ottawa, I had never seen this moth and I wonder if it ever found a mate.