Dome Construction
Dome construction was led by John Mahony, Russ Kaspar, and Bill Hayward, with additional help from Dan Malone, George Wyncott, Ed Harfmann, Terry Steadham, John "J.T." Holman, Hoppy Bray, Jerry Seager, Jay Simmons, Doug Dieter, David Kaspar, Raphael Torres, Jeff Wieland, and Susan Kaspar.
Construction started very similar to the roll-off buildings: a square building with a frame based on 4X4 posts sunk a few feet into the ground. A trench was dug from the binopole for power.

Then floor joists were installed, except near the center, and a form and rebar cage for the center pier (18" square, 4' deep, with about 2' more above ground) was built. Concrete was poured for the posts and pier, and then the center joists were added. 3/4" plywood was used for the floor, and the wall framing was covered with OSB panels. Triangular plywood panels were added on top in the corners as the base for the roof corners, leaving (at this point) an octagonal opening for the dome.
This shows the partially constructed new building at the south (upper left) part of the observatory grounds, south of the binopole at center.

Then small plywood pieces were added to convert the octagonal roof opening to a circle, the roof corners were covered with roofing material, the roof ring for the dome was built on top, and then steel siding was added, and a wheelchair ramp was built:
The base building is done except for steel siding in front and the door.

With the last steel siding and a door:
In the center, a temporary structure was built on the pier to mark the center at rooftop height. 
This was actually added before the roof ring was added, as an aid in making sure the ring was properly circular and centered.

Building the base building was easy, since we had done it before.
But building the dome itself lived up to its reputation for difficulty...