Ron Wanttaja writes:

The actual size of an aircraft at 3 miles is probably smaller than the projected
size of the monitor's pixel.

Probably. I turned on the headings for MSFS and I still could not see
the aircraft--it was indeed smaller than one pixel, so there was
nothing there. It has to be about 1 nm away before I can see a pixel
moving (for small aircraft).

It's your predator instincts that help pick out
the airplane (e.g., "something's moving"), not the physical size of the dot.

Unfortunately there's a lot of aliasing on a computer display, so lots
of pixels are changing.

The aircraft configuration isn't identifiable until it gets quite close, and not
by type until it gets even closer. Though I once ID'd a friend's airplane at
about three miles due to its color....

Real-life normal vision should be able to see an aircraft moving at a
greater distance than on a computer screen, I think, especially in
clear air (most computer screens do not fully tax human visual
acuity).

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