The forward frame of the optics support structure (OSS) was brought to the summit on September 2. Before it could be mounted on the mirror cell, the following steps had to be taken:

1. The dummy mirror had to be transported to the summit and installed in the mirror cell.
2. The truss members had to be installed on the face-down forward frame.
3. The assembled OSS had to be inverted and lifted into the chamber

The dummy mirror came up the mountain on Monday, September 14 and was installed in the cell that afternoon. Assembly of the truss had already begun and was completed on September 15. The OSS was inverted in a complex set of moves and the last two members were installed and the assembly was then lifted into the chamber. The latter move was very difficult and complex -- clearances are extremely tight and precise positioning of the crane and the MMT building were necessary. This was done in spite of cool temperatures and a moderate wind under threatening skies. Some last-minute solutions to problems of tight clearances were necessary and the OSS was bolted onto the cell by 2:00 PM.

Once again, the crane was from Marco Crane & Rigging, Sierita Mining and Ranching handled the trucking and the entire operation was directed by J.T. Williams.

• The dummy mirror comes up the hill behind the Common Building, followed by the pusher loader.
• Onto the land bridge.
• Up to the summit parking lot.
• Final positioning of the dummy.
• The partially-assembled OSS.
• Halfway through inverting the OSS.
• Lifting to vertical.
• A little more...
• ...more...
• ...vertical!
• One of the last two truss tubes is lifted with the small crane.
• The tube is moved into position and bolted to the OSS by Dennis, Mike and Phill.
• The complete OSS is lifted...
• ...and rotated into the proper alignment.
• The flying OSS...
• ...approaches the building....
• ...moves into position...
• ...everybody holds their breath...
• ...as the OSS is cleared for final approach.
• The view from inside the building.
• A quick look at one of the counterweight assemblies.
• The OSS moves in.
• A little closer.
• Above the cell.
• Guiding the trusses.
• A view of the connection point for the western truss members.
• The clearance problems occurred at the top of the building.
• Mike Alegria helps to guide the load.
• Connecting the southern truss flange.
• Connecting the eastern truss members.
• Finally, the recalcitrant northern flange bolts are inserted.
• A view from outside.
• Incredible, no?