Angular resolution: about 1 arcminute, approximately 0.02° or 0.0003 radians, which corresponds to 0.3 m at a 1 km distance.
So roughly 3300 linear pixels in the centre field, which is fairly unimpressive compared with most birds or even a cheap desktop scanner. The clever bit is the integrating and interpolating capability of the brain. I remember noting that I could clearly see the 0.5 cm diameter tow rope trailing from an aeroplane 300 m above me - well below the theoretical resolution of a human eye but clearly discernible by a combination of integration, interpolation and training. Much more difficult to see the rigging of a small boat or radio mast at the same distance because they aren't moving across the visual field.
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