The Discovery Channel Telescope (DCT) is a project of Lowell Observatory, undertaken with support from Discovery
Communications, Inc., to design and construct a 4-meter class telescope and support facility on a site approximately 40
miles southeast of Flagstaff, Arizona. The Discovery Channel Telescope Enclosure was completed in November, 2009.
The DCT Enclosure is an octagonal steel structure with insulated composite panel skin. The structure rotates on sixteen
compliant bogie assemblies attached to the stationary facility. The shutter is composed of two independently actuated, bi-parting
structures that provide a viewing aperture. To improve seeing, the skin is covered with adhesive aluminum foil
tape and the enclosed observing area is passively ventilated via rollup doors. The observing area can also be actively
ventilated using a downdraft fan, and there are provisions for upgrades to active air conditioning. The enclosure also
includes operational equipment such as a bridge crane, personnel lift, and access platforms.
This paper discusses some of the design trades as well as the construction challenges and lessons learned by the DCT
Project, its designer M3 Engineering and Technology Corporation (M3), and its general contractor, Building and
Engineering Contractors, Southwest (BEC Southwest).