世界最大單口徑射電望遠鏡工程進展順利

[philip425]

資料來源 :

http://news.ifeng.com/gundong/detail_20 ... 34_0.shtml

http://news.ifeng.com/gundong/detail_20 ... 83_0.shtml

[bingsze]

正啊！謝謝分享！



還有，大家知不知國家總是在建大的射電，其他的光學總不是這麼大呢？

[Eddy So]

謝謝分享！

[wtyu21]

只怕處於雲貴高原地震帶的這個 ‘500米超大鑊“，怕不怕地震的考驗～

[bingsze]

只怕處於雲貴高原地震帶的這個 ‘500米超大鑊“，怕不怕地震的考驗～

http://image.wenweipo.com/2011/03/21/ch11.jpg

這區不是地震帶，而且，地震的破壞力集中在震源四周，應該不是問題。

如果太擔心，就甚麼也不敢起了。

反而要保證質量，不許偷工減料才對！

[wtyu21]

只怕處於雲貴高原地震帶的這個 ‘500米超大鑊“，怕不怕地震的考驗～

http://image.wenweipo.com/2011/03/21/ch11.jpg

這區不是地震帶，而且，地震的破壞力集中在震源四周，應該不是問題。

如果太擔心，就甚麼也不敢起了。

反而要保證質量，不許偷工減料才對！

另一方面，雲貴高原常年雲霧遮天，射電望遠鏡應該可以穿越雲層接收天體射電源吧？

[philip425]

正啊！謝謝分享！



還有，大家知不知國家總是在建大的射電，其他的光學總不是這麼大呢？

技術問題 !? 好像自 2.16米之後, 就沒有更大的單一鏡片, 即使 LAMOST 的 6.67米×6.05米球面主鏡亦是由 37 塊球面鏡拼接而成的.

[philip425]

只怕處於雲貴高原地震帶的這個 ‘500米超大鑊“，怕不怕地震的考驗～

http://image.wenweipo.com/2011/03/21/ch11.jpg

這區不是地震帶，而且，地震的破壞力集中在震源四周，應該不是問題。

如果太擔心，就甚麼也不敢起了。

反而要保證質量，不許偷工減料才對！

另一方面，雲貴高原常年雲霧遮天，射電望遠鏡應該可以穿越雲層接收天體射電源吧？

只要不是行雷閃電, 應該無問題啩 !?

[philip425]

不經不覺快兩年了

http://www.chinanews.com/tp/hd2011/2014 ... 7598.shtml

[bbsdma]

雲貴潮濕多雨，好奇水是怎麼排走的。 溶岩地區地下河？

[鄧登凳]

雲貴潮濕多雨，好奇水是怎麼排走的。 溶岩地區地下河？

按http://arxiv.org/ftp/arxiv/papers/1105/1105.3794.pdf的資料, 那個溶蝕形成的窪地疏水性很好, 沒有水浸; 但為保障望遠鏡安全, 有預算建一條(去水的)隧道。

There is no inundation of karst depressions because of their good drainage, but a tunnel is still budgeted in order to ensure telescope safety.

[bbsdma]

Thanks 鄧Sir for your information.

May I ask another question? Considering the scale of the project, I guess the cable-suspending receiver unit must have some unwanted movements during observation, caused by wind.
In this case the capstans adjustments might not catch up with the cable vibration.
Is it necessary to employ active position actuators to maintain the sub-arcsecond pointing accuracy? If yes where are the actuators installed to?

雲貴潮濕多雨，好奇水是怎麼排走的。 溶岩地區地下河？

按http://arxiv.org/ftp/arxiv/papers/1105/1105.3794.pdf的資料, 那個溶蝕形成的窪地疏水性很好, 沒有水浸; 但為保障望遠鏡安全, 有預算建一條(去水的)隧道。

There is no inundation of karst depressions because of their good drainage, but a tunnel is still budgeted in order to ensure telescope safety.

[鄧登凳]

Thanks 鄧Sir for your information.

May I ask another question? Considering the scale of the project, I guess the cable-suspending receiver unit must have some unwanted movements during observation, caused by wind.
In this case the capstans adjustments might not catch up with the cable vibration.
Is it necessary to employ active position actuators to maintain the sub-arcsecond pointing accuracy? If yes where are the actuators installed to?

According to http://arxiv.org/ftp/arxiv/papers/1105/1105.3794.pdf, the cable suspended "receiver" actually has a three-layer structure. The top layer called the star frame is suspended by six steel cables. It is equiped with GPS and laser guiding system to achieve an accuracy of 100mm. Below it is the independent fine adjustment system to achieve the required position accuracy. The extracted diagram describes the fine adjustment

[bbsdma]

Thanks 鄧sir for that. The pdf file you provided is very informative, excellent material for me to learn.

Thanks 鄧Sir for your information.

May I ask another question? Considering the scale of the project, I guess the cable-suspending receiver unit must have some unwanted movements during observation, caused by wind.
In this case the capstans adjustments might not catch up with the cable vibration.
Is it necessary to employ active position actuators to maintain the sub-arcsecond pointing accuracy? If yes where are the actuators installed to?

According to http://arxiv.org/ftp/arxiv/papers/1105/1105.3794.pdf, the cable suspended "receiver" actually has a three-layer structure. The top layer called the star frame is suspended by six steel cables. It is equiped with GPS and laser guiding system to achieve an accuracy of 100mm. Below it is the independent fine adjustment system to achieve the required position accuracy. The extracted diagram describes the fine adjustment

[Chanlunlun]

正啊！謝謝分享！



還有，大家知不知國家總是在建大的射電，其他的光學總不是這麼大呢？

Three reasons :-

1. lack the technology to grind, polish and figure 10m class mirror.

2. lack the suitable site to place 10 m class telescope. Even around the whole world such site is still rare.

3. break throughs in optical astronomy may comes not as fast as those from radio astronomy. Better c/p ratio in radio astronomy.