Tonight I've looking at an optical phenomenon presenting as rather large ring around the moon. I'm thinking it's probably a 22 degree halo, but it seems kind of big... maybe 46.
Anyway, I realised I had no good way of estimating the angle between the moon and the ring. Does anyone know any good rules of thumb for judging visual angles without instrumentation?
I found this, but perhaps there are other ways? Maybe there are some tricks to using it more effectively.