Observers at the La Silla Observatory, located in Chile's Atacama Desert, were studying the stars and constellations last week when they saw something spectacular: a bright lunar halo formed in front of the constellation Orion and the brightest star in our sky, Sirius, reports The Washington Post.
Like solar halos, lunar and solar halos belong to the family of ice halos, which are optical phenomena that result from the refraction of the sun's rays in hexagonal ice crystals suspended high in the atmosphere, most often in cirrus clouds. They are also known as 22-degree halos because the ring of light forms 22 degrees from the Sun.
Cirrus clouds are made up of millions of tiny ice crystals. When light from the Sun or Moon hits these crystals in the right direction, the light is refracted and reflected. It is this interaction between light and hexagonal ice crystals that forms a ring around the moon.
Subham Dutta.
While solar and lunar halos form in the same way, there is one notable difference. Because moonlight is not very bright, moon halos are usually colorless compared to their more iridescent solar cousins. However, with perfect optical alignment and ideal camera settings, we can occasionally see color in moon halos - usually red on the inside and blue on the outside.