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The Medicina Radio Observatory is an astronomical observatory located 30 km from Bologna, Italy. It is operated by the Institute for Radio Astronomy of the National Institute for Astrophysics (INAF) of the government of Italy. The site includes: * 32-metre diameter parabolic antenna for observing between 1.4 and 23 GHz. The 32-m antenna is used as a single-dish instrument for astrophysical observations (such as water and methanol maser spectroscopy), SETI experiments and radar monitoring of Near Earth Objects. In interferometric mode it functions as a VLBI station, part of the European VLBI Network (EVN).〔(【引用サイトリンク】title=Home page )〕 * 564 by 640 m (30000 square meter) multi-element ''Northern Cross'' cylindrical-parabolic transit radio telescope for observing at 408 MHz.〔(【引用サイトリンク】title=Description )〕 ==Northern Cross Radio Telescope== The Northern Cross Radio Telescope (Croce del Nord in Italian) is one of the largest transit radio telescopes in the world. Observations are focused around 408 MHz (UHF band), corresponding to 73.5 cm wavelength. The older receivers of the telescope function with a 2.5 MHz wide frequency band, while the upgraded parts have a 16 MHz bandwidth. The telescope is steerable only in declination, meaning that it can solely observe objects that are culminating on the local celestial meridian.〔 The telescope is T-shaped and consists of: * E/W (East-West) arm - Single reflector 560 m x 35 m (1536 dipoles) * N/S (North-South) arm - Array of 64 reflectors 640 m x 23.5 m (4096 dipoles) The telescope can provide 22880 possible theoretical independent beams and has a field of view of 55.47 degrees (East-West) by 1.8 degrees (North-South).〔 The resolution is around 4-5 arcminutes in the North-South direction, and 4 arcminutes in the East-West direction. While less than the resolution of large optical telescopes, the amount of radiation which can be gathered with the Northern Cross is much greater, proportional to the mirror surface of approximately 27400 square meters. Northern Cross represents the largest UHF-band antenna in the Northern hemisphere, with an aperture efficiency of 60%, making it second in the world, after the Arecibo radio telescope.〔 This allows the Northern Cross to identify and measure extremely faint sources, making the telescope is particularly suitable to extragalactic researches.〔 There are plans upgrade of the East-West arm telescope to a LOFAR SuperStation, due to the good performances of a cylindrical-parabolic antenna in the 100-700 MHz frequency range. Since LOFAR operates in the 120-240 MHz range, some of the sensors on the Northern Cross Radio Telescope, optimized for 408 MHz, will have to be replaced with broadband antennas. This installation will have an effective area much larger than any other remote LOFAR station. If extended to the whole 22000 square meters area of the East-West arm, this single element effective area of 20 standard remote LOFAR stations. The resulting system will provide signification improvement in observation sensitivity.〔(【引用サイトリンク】title=LOFAR SuperStation )〕〔(【引用サイトリンク】title=Electromagnetic development of broadband antenna feeding arrays for the Northern Cross Radio Telescope )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Medicina Radio Observatory」の詳細全文を読む スポンサード リンク
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