The 4.3m Discovery Channel Telescope delivers an f/6.1 unvignetted 0.5° field to its RC focal plane. In order to support
guiding, wavefront sensing, and instrument installations, a Cassegrain instrument support assembly has been developed
which includes a facility guider and wavefront sensor package (GWAVES) and multiple interfaces for instrumentation.
A 2-element, all-spherical, fused-silica corrector compensates for field curvature and astigmatism over the 0.5° FOV,
while reducing ghost pupil reflections to minimal levels. Dual roving GWAVES camera probes pick off stars in the
outer annulus of the corrected field, providing simultaneous guiding and wavefront sensing for telescope operations. The
instrument cube supports 5 co-mounted instruments with rapid feed selection via deployable fold mirrors. The corrected
beam passes through a dual filter wheel before imaging with the 6K x 6K single CCD of the Large Monolithic Imager
(LMI). We describe key development strategies for the DCT Cassegrain instrument assembly and GWAVES, including
construction of a prime focus test assembly with wavefront sensor utilized in fall 2011 to begin characterization of the
DCT primary mirror support. We also report on 2012 on-sky test results of wavefront sensing, guiding, and imaging
with the integrated Cassegrain cube.