Figure 3. Installing the last sections of the new primary air seal on VATT. The air seal provides a tight seal of the air that surrounds the primary mirror glass and is essential for accurate temperature control of the mirror. The air seal produces no distortion of the optical mirror surface even though it is in intimate contact with the mirror edge. It also defines the aperture used of the mirror. The seal is readily removable for quick access and easy maintenance of the primary mirror edge support structures, which are seen under the open section.

Photo credit: Richard Cromwell