‘That’s not where the Sun should be this time of morning,’ thought Marie Nicholls (Member 60,824) when she looked to the sky over Malvern, Worcestershire, England. That ‘mock sun’ to the right of the actual one is known as a parhelion, an optical effect that appears when the ice crystals in thin veils of high clouds like these Cirrostratus fibratus act like tiny prisms and refract the sunlight. In the right conditions, these mock suns can appear on both sides of the Sun, flanking it like a pair of faithful hounds. This is why parhelia are popularly known as sun dogs.