This is the second picture of a series of four of the Licorne thermonuclear test in French Polynesia. Thanks for correcting the error, I had quite contradicting evidence, a search in Google showed many of those pictures when searching for Canopus. My mistake.
This is a scan of a (digitally restored) hardcopy of a picture taken by the French army which could be purchased in Tahiti at that time.
Don't forget to have a look at Phil Plait's blog entry on Bad Astronomy about the little pareidolia well hidden inside the flames - blogs.discovermagazine.com/badastronomy/2008/08/13/nukeid...