The telescope is in Sardinia, 35 kilometres (22 mi) north of Cagliari,[1] and is the largest[2] of a set of three telescopes operated by INAF, along with telescopes at the Medicina Radio Observatory and the Noto Radio Observatory. It operates as a stand-alone instrument and as part of global networks of telescopes. The telescope and its structure weighs around 3,300 tonnes (3,300,000 kg).[1]
The primary mirror is 64 metres (210 ft) in diameter. It has an active surface consisting of 1008 aluminum panels in 14 rows. Each panel has an area between 2.4 and 5.3 square metres. There are 1116 actuators mounted on the backing structure, which move the surface panels to correct for the distortion of the mirror with elevation. A quadrupod supports a 7.9 metres (26 ft) diameter subreflector, with 49 panels in three rows, as well as primary focus instrumentation.[1]
The telescope is fully steerable. The telescope sits on a reinforced concrete base, carved into bedrock, with a continuously-welded track sitting on a 40 metres (130 ft) diameter outer ring, connected to the foundations with 260 pairs of anchor bolts, and supporting 16 wheels. In the centre is the azimuth bearing support, as well as the cable wrap and encoder system. The welded steel alidade then supports the elevation wheel, which is in turn connected to the primary mirror backing structure. A room at the base of the alidade holds the motor power supplies, antenna control system, and cryogenic compressors. Three rooms just below the primary surface contain the secondary focus receivers, as well as smaller mirrors and electronics.[1]
The telescope will ultimately have 0.3–115 GHz (1 metre to 3mm) continuous frequency coverage.[1] Initially three receivers were installed: an L band receiver in prime focus, a C-band receiver in the tertiary focus, and a 7-beam K-band receiver in the secondary focus.[3]
The contract to fabricate the telescope structure and mechanics started in 2003, and the construction of the foundations was completed in 2004. The initial schedule was for inauguration in late-2006;[5] construction ultimately was completed in mid-2012.[3]
The telescope was constructed by MT Mechatronics GmbH of Germany. The first light was on 8 August 2012, using the Moon and 3C218 (Alphard). The technical commissioning phase ended in 2013, and formal inauguration was on 30 September 2013,[1] with scientific commissioning between 2012 and 2015. Its first VLBI connection was in January 2014.[3]
^ abCortes-Medellin, G. (June 2002). "The 64 m Sardinia radio telescope optics design". IEEE Antennas and Propagation Society International Symposium (IEEE Cat. No.02CH37313). Vol. 4. pp. 136–139 vol.4. doi:10.1109/APS.2002.1016944. ISBN0-7803-7330-8. S2CID119437534.
