Andrea Maccaferri

Sardinia Radio Telescope: the new Italian project

This contribution gives a description of the Sardinia Radio Telescope (SRT), a new general purpose, fully steerable antenna proposed by the Institute of Radio Astronomy (IRA) of the National Institute for Astrophysics. The radio telescope is under construction near Cagliari (Sardinia) and it will join the two existing antennas of Medicina (Bologna) and Noto (Siracusa) both operated by the IRA. With its large antenna size (64m diameter) and its active surface, SRT, capable of operations up to about 100GHz, will contribute significantly to VLBI networks and will represent a powerful single-dish radio telescope for many science fields. The radio telescope has a Gregorian optical configuration with a supplementary beam-waveguide (BWG), which provides additional focal points. The Gregorian surfaces are shaped to minimize the spill-over and the standing wave between secondary mirror and feed. After the start of the contract for the radio telescope structural and mechanical fabrication in 2003, in the present year the foundation construction will be completed. The schedule foresees the radio telescope inauguration in late 2006.

Status of the Sardinia Radio Telescope project

We present the status of the Sardinia Radio Telescope (SRT) project, a new general purpose, fully steerable 64 m diameter parabolic radiotelescope capable to operate with high efficiency in the 0.3-116 GHz frequency range. The instrument is the result of a scientific and technical collaboration among three Structures of the Italian National Institute for Astrophysics (INAF): the Institute of Radio Astronomy of Bologna, the Cagliari Astronomy Observatory (in Sardinia,) and the Arcetri Astrophysical Observatory in Florence. Funding agencies are the Italian Ministry of Education and Scientific Research, the Sardinia Regional Government, and the Italian Space Agency (ASI,) that has recently rejoined the project. The telescope site is about 35 km North of Cagliari. The radio telescope has a shaped Gregorian optical configuration with a 7.9 m diameter secondary mirror and supplementary Beam-WaveGuide (BWG) mirrors. With four possible focal positions (primary, Gregorian, and two BWGs), SRT will be able to allocate up to 20 remotely controllable receivers. One of the most advanced technical features of the SRT is the active surface: the primary mirror will be composed by 1008 panels supported by electromechanical actuators digitally controlled to compensate for gravitational deformations. With the completion of the foundation on spring 2006 the SRT project entered its final construction phase. This paper reports on the latest advances on the SRT project.

Commissioning of the Sardinia Radio Telescope in Italy: Results and perspectives

On 30 September 2013, the opening ceremony of SRT has signed the contractual ending of the instrumental commissioning of the Sardinia Radio Telescope. In February 2014 it has been completed also the “fine tuning process” aimed at defining the first optimizations parameters needed to make calibrated radio astronomical observations. Since then, the final Astronomical Validation, that was just started in parallel with the previous activities, has taken the lead of the users allocated time. At the time of the real presentation in August we expect to be able to present the experimental quantitative results of the commissioning that at the time of this writing are still under analysis.

Status of the radio receiver system of the Sardina Radio Telescope

In this article, we present the design and performances of the radio receiver system installed at the Sardinia Radio Telescope (SRT). The three radio receivers planned for the first light of the Sardinian Telescope have been installed in three of the four possible focus positions. A dual linear polarization coaxial receiver that covers two frequency bands, the P-band (305-410 MHz) and the L-band (1.3-1.8 GHz) is installed at the primary focus. A mono-feed that covers the High C-band (5.7-7.7 GHz) is installed at the beam waveguide foci. A multi-beam (seven beams) K-band receiver (18- 26.5 GHz) is installed at the Gregorian focus. Finally, we give an overview about the radio receivers, which under test and under construction and which are needed for expanding the telescope observing capabilities.