Author Topic: Arecibo radio telescope destroyed.  (Read 2580 times)

ElyDave

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Re: Arecibo radio telescope destroyed.
« Reply #25 on: 03 December, 2020, 09:14:59 pm »
Pretty much shows why it was unsafe to attempt repair
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Feanor

  • It's mostly downhill from here.
Re: Arecibo radio telescope destroyed.
« Reply #26 on: 03 December, 2020, 09:47:49 pm »
It says in the article that the platform weighed in at 900 tons.
Not sure if that's right.

But one thing I did note was that the support cables are almost horizontal!
The tension in them must be incredible!

Re: Arecibo radio telescope destroyed.
« Reply #27 on: 03 December, 2020, 10:05:40 pm »
It says in the article that the platform weighed in at 900 tons.
Not sure if that's right.

The bit that fell is the size of a building, "about five stories tall": https://www.youtube.com/watch?v=QZAWqk-wrzc&t=6m50s

Re: Arecibo radio telescope destroyed.
« Reply #28 on: 03 December, 2020, 10:21:19 pm »
Given that the azimuth arm on the underside of the platform, from which antennae and sub-reflectors were hung, is over 90 metres long, the stated weight (which is probably for the entire triangular platform+azimuth arm+antennae) seems to be reasonably plausible.

Quote
The receiver was on an 820-tonne (900-short-ton) platform suspended 150 m (492 ft) above the dish by 18 cables running from three reinforced concrete towers, one 111 m (365 ft) high and the other two 81 m (265 ft) high, placing their tops at the same elevation. The platform had a rotating, bow-shaped track 93 m (305 ft) long, called the azimuth arm, carrying the receiving antennas and secondary and tertiary reflectors.

https://en.wikipedia.org/wiki/Arecibo_Telescope#General_information

The telescope description page on the NAIC web site also says 900 short tons, though it says the azimuth arm is longer than what El Wiki says it is.

Quote
Suspended 450 feet above the reflector is the 900 ton platform. Similar in design to a bridge, it hangs in midair on eighteen cables, which are strung from three reinforced concrete towers. One is 365 feet high, and the other two are 265 feet high. All three tops are at the same elevation. The combined volume of reinforced concrete in all three towers is 9,100 cubic yards. Each tower is back-guyed to ground anchors with seven 3.25 inch diameter steel bridge cables. Another system of three pairs of cables runs from each corner of the platform to large concrete blocks under the reflector. They are attached to giant jacks which allow adjustment of the height of each corner with millimeter precision.

Just below the triangular frame of the upper platform is a circular track on which the azimuth arm turns. The azimuth arm is a bow shaped structure 328 feet long.

https://www.naic.edu/ao/telescope-description
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