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1.Introduction |
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1.Introduction |
The Sardinia Radio Telescope (SRT) is a shaped gregorian 64 m single dish radio telescope under construction in Sardinia (Italy), which should be operating by December 2008.
Fig. 1.1 : SRT
The main features of SRT will be the following :
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Continuous frequency coverage in the range 0.3÷100 GHz |
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Multibeam receivers (the 22 GHz already under construction) |
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Active surface |
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Free setting of the primary reflector profile (parabolic for primary foci observations, shaped for gregorian foci observation) |
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Fast secondary mirror wobbling (wobbling time ≤ 1 sec) |
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Totally remote controlled system |
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Frequency agility |
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Wide band receiver systems |
| Position | Pranu Sanguni (CA), Italia |
| Coordinates | Lat. 39°29'50'' N - Long. 09°14'40'' E |
| Optics | Gregorian (shaped) + BWG |
| Frequency coverage | 0.3÷100 GHz |
| Primary reflector diameter | 64 m |
| Secondary reflector diameter | 8 m |
| BWG reflectors diameters | 2.9÷3.9 m |
| Multibeam receivers | 22 GHz (7 feeds) |
| Available foci |
Primary f/D = 0.33 Gregorian f/D = 2.34 2 x BWG I f/D = 1.38 2 x BWG II f/D = 2.81 |
| Elevation range | 5°÷90° |
| Azimut range | ± 270° |
| Parallactic angle range | ± 60° |
| Slew rates (wind speed < 60 km/h) |
0.85 °/sec Azimuth 0.5 °/sec Elevation 10°/sec Parallactic angle |
| Surface accuracy (rms specified) |
630 micron (passive surface) 185÷119 micron (active surface) |
| Pointing (rms specified) | 11÷1.8 arcsec |
| FWHM Beamwidth | 19.5 arcmin/f (GHz) |
| Gain | 0.4÷0.7 K/Jy |
| First secondary lobes | ≈ 20 dB under the main lobe |
| Receivers mounts |
Primary focus : retractable positioner (4 receiver's bays) Gregorian focus : rotating turrett (8 receiver's bays) BWG I-II : fixed (4 receiver's bays) |
Tab. 1.1 : SRT Characteristics
Observations at the lower frequencies (0.3 ÷ 22 GHz) will be possible at the very early stage of the commissioning program. Once the active surface will be tested at these frequencies, then the higher frequencies (22 ÷ 100 GHz) will be also available.
To see the current state of the building works, click HERE.
The following picture shows the comparison (scale drawing) between SRT and the existing Medicina radiotelescope (32 m diameter).In the picture a man 1,87 m tall is shown also.
Fig. 1.2 : Comparison between SRT and Medicina's antenna
