UNIDENTIFIED alien spacecraft, a quirk of digital photography or a case of extra-terrestrial fraud?
These are some of the hundreds of "UFOs" that a biochemist-turned-school teacher says he captured on his $600 digital camera from the veranda of his Darlington home in the Perth Hills.
Rob Hartland has taken more than 20,000 photos of the day-time sky in the past six months and analysed them on his computer.
It began when he was taking photos of clouds to test out a new camera when he noticed a "smudge" that, when enlarged and enhanced, "had some structure to it, suggesting it could be some sort of craft in the sky".
He says since then he has identified a dozen different UFOs including round, square and saucer-shaped craft, posting the photos to his website wispyclouds.net for extra-terrestrial buffs and sceptics to ponder.
It comes after The Sunday Times last week revealed more than 400 West Australians had sought advice or counselling through the Australian Close Encounter Resource Network after claiming to see UFOs or meeting extra-terrestrials.
"I take about 30 shots at a time. In 10-15 minutes I'll take 300 to 400 images. Then I connect the camera to the computer. I zoom in and enhance any little thing I note on the images and you get these craft in anywhere from 2 per cent to 20 per cent of shots," Mr Hartland said.
"Some of them appear to have transparent canopies and in some shots it looks like there could be occupants inside.
"I always say 'could' rather than 'is'. There is always doubt. But UFO stands for unidentified flying object and as far as I'm concerned these aren't identified. It's possible some are man-made, but I don't think they all are.
"There's no way it is a bird or insect or plane they look totally different and these craft move much faster."
Mr Hartland, who has completed a PhD in biochemistry, said he had no history of mental illness or drug taking and that he never altered his photos, though he acknowledged many people would find his claims hard to believe.
The Sunday Times picture editor Jackson Flindell said Mr Hartland's images did not appear to have been tampered with, but dust on a digital camera's image sensor could cause anomalies in digital photographs, while powerful magnification could also distort images in some cases.