Arecibo Observatory (located near the town of
Arecibo in
Puerto Rico) is home to the world's largest
radio telescope. The
telescope consists of a 305-meter
spherical dish which collects incoming radio waves and focuses them onto a group of
receivers housed in a dome suspended from a
platform some 400 feet from the bottom of the center of the dish. Three towers placed equidistantly around the dish provide support for the dome, which is suspended by an arrangement of cables.
The main reflector dish (the 305-m one) is actually made up of several thousand individual panels. When it comes time to
check the alignment of the dish and correct it for shape, workers go out under the dish and manually adjust several thousand screws that are responsible for the positioning of each separate
panel.
The surface of the reflector is constructed from a fine
mesh, which is made possible by the extremely long
wavelengths of the
radio waves being collected. The mesh allows
sunlight to pass directly through the dish, and produces a thriving
ecosystem with surprisingly lush
vegetation. (Supposedly it also has the perfect conditions for growing
pot, but what with it being a nationally funded
research facility, let's forget that for the moment.) However, contrary to the view painted in the movie
Golden Eye -- parts of which were filmed at Arecibo -- the mesh
does not hold water. (People have been known to call and ask what days the dish will be filled with
water so they know not to come for the
tour that day.)
On the observatory grounds are a number of
housing units where visiting
scientists can stay for the length of their observing run, a full-service
cafeteria serving
authentic (if rather greasy)
Puerto Rican cuisine, and two office buildings. There is also a
LIDAR facility, which uses a technique similar to radar to probe the
ionosphere, only instead of radio waves, it makes use of light waves in the form of several high power
lasers. There is also a trailer that is home to the
SETI Pegasus Project which gathers data from the telescope for use with its
SETI@home efforts.
The
Arecibo Observatory Visitor's Center has a number of
educational displays and an observation deck with a great view of the dish and dome. The Visitor's Center also shows a short
documentary film on the day-to-day activities of the observatory on a regular basis throughout the day.