Super talented stone mason and all round wonderful person, Matt Driscol was the man given the job of creating an oculus out of stone, actually two of them, ( avoiding the plural ) for the opening over the top of the dome.
The process involved carefully drilling many holes around the circumference in a 24 inch diameter circle in a large flagstone slab of mica schist, and then chiselling and hammering ( disconnecting the dots? ) to eventually dislodge a fully intact circle of stone, and thus thereby creating the round opening in the slab we needed for the dome.
We decided on a second oculus, which he cut out the same way, but first drilled and cut a smaller circumference circle, and then drilled and cut out the final 24 inch ring dimension from that ( you can see the resulting bonus ring of stone hanging on the tree on the right )
The first oculus was hoisted up (via the Gradal) and then lifted by hand over top of the a course of random stone 'tiles' around the roof opening and then, after fitting the final course of (pre-shaped) stones over and around the first oculus, the second oculus was then lifted gently over the top of everything. , creating a kind of semi-watertight seal, and a beautiful finish to the Temple of Imperfections
