Police helicopter captures picture of amazing circular rainbow

By Dean Murray via SWNS

A police helicopter was somewhere .... over a circular rainbow.

A crew member snapped a jaw-dropping picture of the rare sight over the Vale of Glamorgan in South Wales.

The St Athan-based National Police Air Service (NPAS) South West & Wales Region unit said they captured the "great photo" after assisting South Wales Police.

To be able to see a full circle rainbow you need to be able to see water droplets below your observable horizon.

Standing on top of a tall building or looking out of an aircraft can give you the required view of water droplets and sunlight below your observation point.

In theory, every rainbow is a circle, but from the ground, usually, only its upper half can be seen.

Since the rainbow's center is diametrically opposed to the Sun's position in the sky, more of the circle comes into view as the sun approaches the horizon. This means that the largest section of the circle normally seen is about 50% during sunset or sunrise.

It is possible to produce the full circle when standing on the ground by spraying a water mist from a garden hose while facing away from the sun.