Moon rings and sun dogs

When the air is just right, a large ring appears around the moon. A similar effect makes it look like three suns are rising at once; this may have helped the English king Edward IV win the Battle of Mortimer’s Cross in 1461.

Ice crystals in the air can do funny things. The moon ring, also known as the 22° halo, forms when hexagonal crystals refract the moon’s light and form a solid white ring. This is sometimes accompanied by little bright spots known as parhelia, or informally known as moon dogs.

The sun also forms parhelia in the right conditions – effectively, it looks like three suns instead of one. These so-called sun dogs are a rare but well-known meteorological phenomenon.

One famous instance of sun dogs occurred in the War of the Roses, just before the Battle of Mortimer’s Cross. The House of York (led by Edward, later King Edward IV) faced off against the House of Lancaster. At sunrise, before the battle, three suns rose into the sky.

Edward took it as a sign – or at least convinced his troops that it was a sign. Shakespeare described it as follows:

Three glorious suns, each one a perfect sun;
Not separated with the racking clouds,
But sever’d in a pale clear-shining sky.

Edward’s troops won the day.

• 22° halo
• Sun dog
• Battle of Mortimer’s Cross