The vacuum head is mounted on the mirror cell and the plumbing is being put in place for a full test of the vacuum system. The dummy mirror is in the cell. The principal reason for the test is to measure the deformation of the cell under the vacuum load.

• The back of the mirror cell showing the vacuum covers and the plumbing from the cell's central cone.
• Another view of the cell.
• A close-up of the cone.
• The top of the cell showing the removable beam that supports the bell jar duing installation. Also visible are the hoists for the scaffold that allows service of the systems within the bell jar.
• The view from above.
• The vaccum hoses penetrate the back wall of the chamber.
• A view of the front of the bell jar showing the vacuum line emerging from the central port.
• A panoramic view of the bell jar inside the OSS. For a very lage version of this image, click here.
• The vacuum pumps outside of the MMT building.
• Another view of the pumps.
• The roots blower.
• The turbo molecular pump nearly in place.
• A view of the Summit Support building showing the new reinforcing gabions behind which the conditioned air duct will run.
• A view of the horizon-pointing telescope.
• Looking down on the back of the cell.
• Another view of the rear fo the cell.
• The vacuum chamber.