Ring round the moon

This may be common as old boots, but the first time I've seen it.

Last night, around midnight, hazy, (no stars visible) and the moon had a
"rain tomorrow" (not yet!) fuzzy halo, there was a clear compltete bright
circle all round it at quite a distance.

The moon was close to fully overhead.

The radius was about a hand lengthways span at arms length, say about 15
degrees.

Is this a common phenomenon?, I've not seen it before, and is the clear
complete circle common.

I guess it's like rainbows, or sundogs, but would appreciate confirmation

thanx

mike