Most people who have an interest in astronomy (or atmospheric phenomena) will know the usual tricks for measuring angles and distances in the sky. The general idea is that you hold your hand at arm's length and, using difference parts of your hand, held in different ways, get a reasonable measure.
But how accurate is this approach?
Robin Scagell, via a post on the SPA BB, aims to find out:
I would like to find out what is the average dimension of a hand span in degrees. It is often said that a full hand span at arm's length is 20°, but I would like to get some accurate figures on this. So I have checked the distances between several well-known stars in the early evening sky and would like people to go out and test it for themselves.Have a look Robin's post for full details of the experiment.