DEIMOS consists of a rotating structure supported by a cradle assembly located on the right Nasmyth platform of the Keck II telescope. DEIMOS can be moved from the science position to a storage position when not in use. The cradle is supported on rollers, driven by a tractor drive during transport and positioned on kinematic mounts for observing. The rotating structure consists of a drive disk supported by a friction drive, a shell supported on the back by a bearing and a front end that protrudes into the elevation bearing of the telescope. There is a cable wrap at the rear of the instrument to provide 730 degrees of rotation of the rotating structure. Top level assembly drawing is D0001. Drawing D0000 is a family tree of the assembly drawings and numbers. D0002 specifies DEIMOS position angles.
Electronics bays are provided on both the cradle and rotating structure. These bays are actively cooled with glycol heat exchangers. The schematic for the glycol cooling is D0800.
The DEIMOS 6-Month Preventative Maintenance Plan is described in the following link.
The optical layout consists of the following components:
A BK-7 window and a pneumatic hatch close the front of the instrument. Assembly drawing is D8740.
The Slit Mask System consists of a cassette with a capacity of 11 masks, a form to position the mask properly at the focal surface and mechanisms to select and insert masks with control from the DEIMOS GUI. The selection is accomplished by moving the cassette with a scissor actuator. The insertion is accomplished by an air cylinder. The mask is located so that it forms a cylindrical approximation of the spherical focal surface. The mask is located on the cylindrical surface of the form by the insertion "hot dog" pressing against 3 rollers that act as hard points. Other guides and rollers insure that the mask inserts into its proper position. Slit mask assembly drawing is D1100 (1 of 2, 2 of 2).
The Cassete Cleaning Procedure is part of the 6-month PM plan.