The strange upside-down V-shaped object in the night sky over North Mayo on Wednesday night had all the appearance of a UFO – but the truth is far less exciting if nonetheless interesting.
I inadvertently photographed this unusual red and green shape set against the magnificence of a star-filled Milky Way sparkling over Lacken along Mayo’s Wild Atlantic Way.
Thanks to the wonders of long exposure photography, I have been able to bring an extra dimension to my life-long interests in astronomy and photography in recent years by photographing the beauty of the Mayo dark skies.
So what’s the strange object that could pass for a UFO, I hear you ask?
Well, it’s nothing more exciting than two jet airliners passing each other at different altitudes at 22.05 GMT on Wednesday, 21 September 2016.
I could see the flashing lights of the planes passing overhead as I took the image, but it didn’t occur to me at the time that the long exposure image would capture the planes’ beacons as light trails creating this unusual picture.
Optical Illusion
When I got home I checked the flight tracker app, Planefinder – which I have written more about here – to identify the two planes and their flight paths. (see Planefinder screenshot below)
The plane on the left is the Moscow-based AzurAir Boeing 767-300 flying at an altitude of 35,000 ft, and at a speed of 505knots, heading northeast. The plane on the right is a Qatar Airways 777-200LR, flying at 32,000 ft, and heading west out over the Atlantic, at 487knots.
The complex scientific explanation for the optical illusion is beyond me, but here’s my own layman’s reasoning.
The optical illusion that makes it seem as if the two planes are flying upwards at a steep angle is, in this case, partly due to the distortion perspective phenomenon caused by wide-angle camera lenses, known as converging verticals. You will often see this distortion in photos of tall buildings. I was using the superb Samyang 12mm F2 wide angle lens at the time, but this was not entirely the cause of the perspective distortion
You can also notice perspective distortion when a distant plane is flying directly towards you – typically from the south here in North Mayo – it appears to go straight up from the horizon. This also is due to perspective causing an optical illusion as the plane comes over the horizon – and this may also have been at play when I took the photo.
If anyone can explain this better please feel comment below.
The green and red light trails that combine to form the upside-down V shape are wing tip lights which are part of an aircraft’s array of safety and warning lights. The red beacon is always on the left wing tip of a plane – and the green is always on the right.
The small building in the left foreground is an old World War 11 coast watching lookout post (LOP) that is now in disrepair. There is talk in Lacken about restoring the old structure where local men once kept watch for intruders during The Emergency under the same beautiful star-studded Milky Way.
MAYO.ME 