'Flying Banana' traveling 125 mph fires laser into sky and catches aurora hunters off guard (video)

On two separate nights in May, a strange blue laser sliced through the skies over the Oxfordshire, England countryside, leaving skywatchers baffled. Astrophotographer and astronomy communicator Mary McIntyre captured the eerie spectacle on her remote aurora-hunting cameras — and what she saw didn't match anything she'd encountered before.

"The first time I spotted it [May 1], I thought at first it may have been a rare form of blue aurora but then realised it was moving too quickly," McIntyre told Space.com in an email. "It just didn't fit with any other aurora we've seen during the 30 or so displays we've captured."

Suspecting a spotlight from a nearby RAF base sometimes used for film sets, McIntyre considered that theory, then ruled it out due to the light's speed.

Maybe lights from a festival? McIntyre had seen those before, too, but not like this. "We've had lights from festivals before now, but again they looked nothing like this, plus this blue beam was in the sky in the early hours of the morning rather than evening."

It wasn't until McIntyre's husband shared the footage from May 1 that a friend in the astronomy community offered an explanation — a high-speed mapping train with a fruity nickname.

The culprit for the strange blue light show is a specialized train that records track condition information using lasers at speeds of up to 125 mph. It is officially known as the New Measurement Train (NMT), but its bright yellow paintwork has earned it the playful nickname "Flying Banana".

"I couldn't believe it when I spotted it on our cameras again in the early hours of 29th May!" McIntyre said.

"While it looks very cool, it's also a shame to have yet another thing that's polluting the night sky," McIntyre continued.