Below is a picture from the library, the weather today has been frankly awful and a decent picture nigh on impossible.  Aeration started today on the Abbotts greens.  This piece of equipment produces a hole 10mm in diameter and up to 10 inches deep.  We have opted to go 6 inches deep.  The machine takes about 25 minutes on each green and leaves a slightly elongated hole on the surface of the green.  Normally we would cut and roll greens after but with the very cold weather we have opted to double roll with the greens mower so as not to stress the turf to much. This kind of very deep aeration is a once yearly operation to try and open up the profile and allow air and water to penetrate deeply into the green.  We would expect the green to remain bobbly for 3-4 days before returning to its usual position.