Halo

Had a lovely day walking with several friends and our respective dogs at Cardinham.
Tried to get a photo of 7 dogs together (my spaniel and dalmatian, a collie, a Labrador, a vizela, a Tibetan terrier and a Newfoundland poodle cross) but it proved impossible despite loads of Primula cheese ;-)
While we were chatting and enjoying cake and coffee after we noticed this halo around the sun

A halo is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in the atmosphere.
The ice crystals responsible for halos are typically suspended in cirrus or cirrostratus clouds in the upper troposphere (5–10 km (3.1–6.2 mi)), but in cold weather they can also float near the ground, in which case they are referred to as 'diamond dust'. So Wikipedia says