The Wheel is actually a big calendar
An astronomer, John Eddy, discovered just recently(1970’s) that this wheel actually was created to mark the passage of time, like a calendar does
If you stand at a certain small cairn on the first day of summer- June 21st- you will see the sun rise directly over the large cairn in the center of the wheel.
The wheel also shows where certain bright stars shine on certain days, each about 28 days apart, like months