CALGARY -- A Calgary photographer who captured a fireball streaking across the night sky says he thought he'd witnessed a plane crashing or a meteor breaking up.

But Neil Zeller says NASA says it was a rocket body returning to Earth after a Chinese satellite launch in December.

Zeller was photographing the northern lights west of Calgary around 11 p.m. on Monday when he caught a flash out of the corner of his eye.

He swung his camera around and was able to get four, long-exposure shots as the unusual light streaked across the sky.

Zeller says it was a "one in a million" experience and a bit of a fluke that he was able to get the photos at all.

He credits the brightness of the aurora borealis Monday night.

"A lot of times a bright object in a dark sky will overexpose. You'll just get a beam of light," he said. "For me to get the individual streaks of light, the individual parts that were burning up in the sky, it was basically a factor of how bright the auroras were."

Zeller explained why the initial sighting was confusing.

"I thought it might have been a plane crashing, just because it was in so many pieces and it was such a big ball," he said. "(But) it didn't appear to be falling. It just kept going across the sky.

"So then I thought maybe a large meteor was breaking up, but it was just way too slow."