72 inch Hubble mirror prototype???

Anybody know what mirror the story is talking about? The actual Hubble
primary is considerably bigger.

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http://www.unm.edu/~market/cgi-bin/archives/001283.html

June 21, 2006
UNM astronomers search for precision with new ground-based telescope
New telescope to provide distinct record of universe

Astronomers at the University of New Mexico are developing an exciting
new telescope with capabilities that are unrivaled in astronomy
circles. The CCD/Transit Instrument with Innovative Instrumentation, or
CTI-II, is a special-purpose telescope where accuracy and precision are
the key components allowing for unprecedented research opportunities.

[snip]

The telescope, under computer control, uses a prototype mirror six feet
in diameter that was originally designed for the Hubble Space
Telescope.