One thing I should have added to my experimental conditions: Close one eye when positioning and viewing the targets.
The OP says "Angle of view of the human eye..."
Quite right, Peter. We lost track of at least part of the original question. My first reaction to the question, 'what is the field of view of one eye', is that it's more than half the field of view of two eyes as a result of some overlap.
The following article from Wikipedia is interesting and addresses the issue. http://en.wikipedia.org/wiki/Binocular_vision
This extract from that article seems to settle the issue, although I'm not sure if I understand precisely what is meant.
...humans have a maximum horizontal field of view of approximately 200 degrees with two eyes, approximately 120 degrees of which makes up the binocular field of view (seen by both eyes) flanked by two uniocular fields (seen by only one eye) of approximately 40 degrees.
What I think they mean is that, whilst the horizontal FoV using both eyes is 200 degrees, only 120 degrees of this is simultaneously seen with both eyes. In other words, the left eye sees an additional 40 degress on the left which is invisible to the right eye, and the right eye sees an additional 40 degrees of the field on the right, which is invisible to the left eye.
If this is correct, we can deduce that the FoV of a single eye is 100 degrees, approximately equivalent to an 18mm lens, FF 35mm format.
It's also interesting that we humans have a very significant feature in common with snakes. We both have our two eyes positioned on the front of our head.