On June 15th, sky watchers around Iran witnessed a strange and luminous cloud in the night sky. "I have never experienced a similar phenomena," reports veteran astronomer Babak A. Tafreshi of Tehran. Observing alongside two other astronomers, Oshin Zakarian and Pouria Nazemi, he took this picture:

 

 

 

Photo details: Canon 350D, 28mm, ISO 800, f4, 35s.

 

"The object started out patchy, shapeless and dim; it quickly brightened and formed a blue-tinted cone with a nose of magnitude -2 or -3," he says. The cloud raced across the sky "moving about 20 degrees per minute." More images:

 

http://www.spaceweather.com/swpod2007/16jun07/Tafreshi1.jpg

http://www.spaceweather.com/swpod2007/16jun07/Tafreshi2.jpg

http://www.spaceweather.com/swpod2007/16jun07/Tafreshi3.jpg

http://www.spaceweather.com/swpod2007/16jun07/Tafreshi4.jpg

http://www.spaceweather.com/swpod2007/16jun07/Tafreshi5.jpg

http://www.spaceweather.com/swpod2007/16jun07/Tafreshi6.jpg

 

"It was shining blue and moving fast," agrees Amir Hossein Abolfath, another witness from Tehran, who snapped this picture. "Twenty minutes after I saw it, my friend Asghar Kabiri saw the same cloud 900 km away from Tehran in Sa'adat shahr."

 

More images: from Muhammad Saber Karimi of Kermanshah, Iran; from Hossein Haeri Ardekani of Ardekan, Yazd, Iran.

 

Mystery solved? The following explanation is probably correct, but uncertain because of the classified nature of the implicated rocket launch:

 

On June 15th at 11:12 am EDT, an Atlas V rocket launched from Cape Canaveral; its payload was a pair of National Reconnaissance Office ocean surveillance satellites. After the satellites were deployed-- into the wrong orbit, according to media reports--the rocket's malfunctioning Centaur upper stage vented excess fuel, producing the Iranian cloud. The dumping of excess fuel is standard practice for Centaur-boosted launches, and this event is probably unrelated to the Centaur's reported malfunction.