'Lunar halo' moon seen across Devon

A 'lunar halo' moon has been spotted over Devon tonight, showcasing a ring of light that appears around the moon.

It is caused by moonlight refracting through ice crystals in the upper atmosphere.

The Met Office explained that haloes require ice crystals to form; either from high cirrus clouds or free-falling crystals.

Typically, sunlight or moonlight is reflected by ice crystals, producing a white halo.

ABOVE: Lunar halo over Combe Martin. Credit: Tony Gussin

However, if the light rays strike the crystals at a particular angle, some light may be refracted.

In such situations, the halo will have a faint colouration.

The majority of ice crystals are hexagonal, or six-sided, and the most common angle of refraction through such a crystal is about 22 degrees. This is the most frequent type of halo, known as a 22° halo.

The weather service also stated that in the past, haloes and other atmospheric phenomena were used as an empirical form of weather forecasting before the development of meteorology.

There is some truth to this, as the high cirrus clouds that contain the ice crystals required for haloes often signify an approaching frontal system. However, in many cases, the front will be inactive or simply change course, producing no rain.