A couple of weeks ago I posted about estimating the height of a plane by trying to estimate the angle that it subtends (blocks out) in my vision. I was looking at an astronomy website earlier and I was shocked to note that the Moon and the Sun only block out 0.5 degrees each. The plane didn't look as big as the Sun so I must have overestimated the angle. The site suggested using my little finger to help measure angles. My little finger is 15mm across and held out like this is 700mm from my eye. Hence the angle subtended is 15/700 = 0.021 radians or 1.2 degrees. So the full Moon or the Sun would only occupy half as much of my vision as my little finger. I will test this out as soon as possible and re-estimate the angle that the plane blocks out.
