Green Bank 140 Foot Telescope

The Green Bank 140 Foot Telescope is a 43 meter telescope at the Green Bank Observatory (GBO) in West Virginia, the second largest telescope at the site after the Green Bank Telescope (GBT). The 140 Foot Telescope was built in the 1960s and among its uses were some early very-long-baseline interferometry (VLBI) experiments. It has an equatorial mount and is the largest such "dish" telescope that ever used one (but the non-dish Ooty Radio Telescope's mounting qualifies as equatorial). It has been unused since 2019. It was retired earlier in 1999, but brought back into service in 2005 with new instruments and used for ionospheric research, for pulsar hunting, and as a control station for Spektr-R.