SoylentNews is people
SoylentNews
China Builds World's Largest Radiotelescope
According to 9news, construction of the world's largest radiotelescope has been completed. Situated in a hollow in the mountains of China's Guizhou province, the structure includes a 500 m reflector, hence its name Five-hundred-metre Aperture Spherical Telescope (FAST). Unlike the Arecibo telescope, the shape of the reflector can be changed. The receiver was built by the CSIRO.
China's Big Telescope
Reuters reports:
China on Sunday hoisted the final piece into position on what will be the world's largest radio telescope, which it will use to explore space and help in the hunt for extraterrestrial life, state media said.
The Five-hundred-meter Aperture Spherical Telescope, or FAST, is the size of 30 football fields and has been hewed out of a mountain in the poor southwestern province of Guizhou.
Scientists will now start debugging and trials of the telescope, Zheng Xiaonian, deputy head of the National Astronomical Observation under the Chinese Academy of Sciences, which built the telescope, told the official Xinhua news agency.
"The project has the potential to search for more strange objects to better understand the origin of the universe and boost the global hunt for extraterrestrial life," the report paraphrased Zheng as saying.
Original Submission #1 Original Submission #2 Original Submission #3
(Score: 1) by g2 In The Desert on Monday July 04 2016, @03:23PM
At 500m, that's huge.
But is a single 500m reflector larger than the 27 - 25 meter dished of the https://www.nrao.edu/pr/2000/vla20/background/vlafacts [nrao.edu]Very Large Array radio telescope in New Mexico that can be spread over 36km ?
(Score: 3, Informative) by Anonymous Coward on Monday July 04 2016, @04:03PM
Depends on what you are after. If you are after high angular resolution, then the VLA is much better. If you are after low amplitude detection, the VLA has a total collection area of 27 * (25m)^2 * pi = 5.3 ha, while the single 500m reflector has a total collection area of (500m)^2 * pi = 78.5 ha, which is almost 15 times as much.
(Score: 5, Informative) by frojack on Monday July 04 2016, @05:29PM
Depends on what you are after. If you are after high angular resolution, then the VLA is much better. If you are after low amplitude detection, the VLA has a total collection area of 27 * (25m)^2 * pi = 5.3 ha, while the single 500m reflector has a total collection area of (500m)^2 * pi = 78.5 ha, which is almost 15 times as much.
Like the much smaller The Arecibo Observatory (305meter) the limited steer-ability of the FAST radio telescope is limited by its design. You might not have all 78ha available for your intended target, and your reception time is much more limited as well.
There's been an off and on debate about whether Arecibo is actually worth the maintenance cost, its been slowly de-funded over the years, and its continuation is far from assured.
Still FAST is BIG and should capture a lot of energy.
No, you are mistaken. I've always had this sig.
(Score: 2) by JoeMerchant on Monday July 04 2016, @08:08PM
So, I get why you would want a parabolic reflector, but what's the point of a spherical reflector when the energy is coming from far away?
🌻🌻 [google.com]
(Score: 1, Informative) by Anonymous Coward on Monday July 04 2016, @08:42PM
A parabolic reflector must be rotated to face the target, while a spherical reflector can be left in place, with only the receiver moving. Since rotating a dish over about 100m is impractical, spherical reflectors are the only option for huge dishes like Arecibo and FAST.
(Score: 3, Informative) by butthurt on Monday July 04 2016, @09:05PM
They seem to be saying that the FAST reflector can be formed into a parabolic shape, although only a 300 m diameter is usable that way;
http://fast.bao.ac.cn/en/Active-reflector.html [bao.ac.cn]
(Score: 1, Informative) by Anonymous Coward on Monday July 04 2016, @05:26PM
Basically, the amount of light collected by a telescope depends on its area, and the angular resolution depends on its diameter. So a telescope with one large receptor collects more light energy than than one made up of multiple small receptors. But with multiple receptors we can build telescopes with a large diameter by spacing them out.
Thus, this telescope will be able to detect fainter objects than the VLA (distinguishing between those objects and the background) due to its much larger area.
However, the VLA will have higher resolution (distinguishing between objects that appear close to each other) due to its much larger diameter.