This summer we fulfilled a life-long dream (at least for some of us) and visited the Arecibo Observatory in Puerto Rico.
This is the largest single-dish radiotelescope in the world. The reflector is 305 m (1,000 ft) in diameter – a tad bit larger than our home-brewed radiotelescope. The Arecibo system is a semi-transit telescope that has a fixed primary reflector with secondary (Gregorian reflector) and a delay-line feed.