The primary observing instrument is the 64-metre movable dish telescope, second largest in the Southern Hemisphere, and one of the first large movable dishes in the world (DSS-43 at Tidbinbilla was extended from 64 m to 70 m in 1987, surpassing Parkes). After its completion it has operated almost continuously to the present day. The dish surface was physically upgraded by adding smooth metal plates to the central part to provide focusing capability for centimetre and millimetre length microwaves. The outer part of the dish remains a fine metal mesh, creating its distinctive two-tone appearance.
The 18m dish antenna in the foreground of the photo was transferred from the Fleurs Observatory (Mills Cross) in 1963. It was used as a transmit uplink antenna in the Apollo program and has been abandoned since the early 1980s.
The telescope has an altazimuth mount. It is guided by a small mock-telescope placed within the structure at the same rotational axes as the dish, but with an equatorial mount. The two are dynamically locked when tracking an astronomical object by a laser guiding system. This primary-secondary approach was designed by Barnes Wallis.
The receiving cabin is located at the focus of the parabolic dish, supported by three struts 27 metres above the dish. The cabin contains multiple radio and microwave detectors, which can be switched into the focus beam for different science observations.
The observatory is a part of the Australia Telescope National Facility network of radio telescopes. The 64m dish is frequently operated together with the Australia Telescope Compact Array at Narrabri and a single dish at Mopra, to form a very long baseline interferometry array.
During the Apollo missions to the moon, the Parkes Observatory was used to relay communication and telemetry signals to NASA, providing coverage for when the moon was on the Australian side of the Earth.
The observatory has remained involved in tracking numerous space missions up to the present day, including the Mariner 2, Mariner 4, Voyager, Giotto, Galileo and Cassini-Huygens probes. It is also a major world centre for research into pulsars, with more than half of those currently known today discovered at the Parkes Observatory. Between 1997 and 2002 it conducted the HIPASS neutral hydrogen survey, the largest blind survey for galaxies in the neutral hydrogen line to date.