Solving Stonehenge in the simplest way possible… Graphically.
Fig SS2: This is the maximum amount of sky that the sun ever manages to scan at Stonehenge. The sun breaks free 50-degrees clockwise from north and scans a total of 260-degrees on solstice day every year on the 21st June. Everyone who visits Stonehenge on solstice morning to see the sunrise looks out along this 50-degree angle from north.
Fig SS3: But look what happens when we place the sun-arc on top of the moon-arc - the moon commands a small section of sky (about 10-degrees) that the sun never gets to visit! - Not ever!