A 1.25 m (49 in) reflector previously located at Cloudcroft Observatory was acquired in the late 1980s and became operational in the early 1990s.[9][10] It was removed from the TMO web site before June 2003.[11] A 0.4 m (16 in) Ritchey-Chrétien reflector built by RC Optical Systems was attached to an equatorial mount. It was installed in 2003 and removed from the TMO web site before July 2011.[12] It was housed in the dome where the Schmidt camera was previously located. A 0.4 m (16 in) Cassegrain reflector was installed at TMO in 1962.[3] Harvey Mudd College was the main user of this telescope from the 1970s through at least 1991.[10] A 0.27 m (11 in) Schmidt camera owned by JPL operated at TMO from 1985 until at least 1991.[10][13] A 5.5 m (18 ft) millimeter wavelength radio antenna was located at TMO from 1970 until at least 1985.[13] A radio interferometer with dishes of 4.4 m (14 ft) and 3.0 m (9.8 ft) became operational at TMO in 1974.[14]