Renegadenemo wrote:I'd be interested to see the numbers. Can't think how you'd work out the range using height alone from a single point. Hmmm, off to ponder.
Fairly straightforward; the angle which an object subtends in the field of vision of the viewer depends on the distance from the viewer. This is in the ratio of 1:60; i.e. an object 1 foot high that is 60 feet away subtends an angle of one degree. Therefore, if you know the size of the object you are viewing and can measure the angle accurately, you can work out the distance to the object.
My own rough calculations suggest that an 8' high object at half a mile would subtend the same angle as a 7'6" high object that was 140' nearer.
Frankly, I'm splitting hairs here; none of this detracts from the fact that it was Neil who recognised a phenomenon that nobody else had spotted, even though it was staring us all in the face. (No, I'm not giving that away here, go and buy your own copy of the book!)
It is not the critic who counts.....