The four outer stones are oriented to mark the limits of the 18.6 year lunar declination cycle. The center column features a hole drilled at an angle from one side to the other, through which can be seen the North Star, a star whose position changes only very gradually over time.

The same pillar has a slot carved through it which is aligned with the Sun's solstices and equinoxes. A 7/8" aperture in the capstone allows a ray of sun to pass through at noon each day, shining a beam on the center stone indicating the day of the year.