Astronomers are seeing stars after a high-profile squabble over the design of a new world-class giant optical telescope is causing delays to the program.
A project named the Large Optical/Infrared Telescope, was approved by the National Development and Reform Commission (NDRC) in July 2017, and was then enlisted as a key science and technology infrastructure project in the country's 13th Five-Year Plan (2016-20), according to the website of the Center of Astronomical Mega-science, Chinese Academy of Sciences (CAS).
To secure the NDRC funding for the construction estimated at 1.5 billion yuan ($220 million), the plans must be approved by the end of 2018, Science Magazine reported in June.
However, the debate over the telescope design has delayed the decision-making. Some argue that it should have an ambitious new four-mirror system, while others say that it is better to use the tried-and-tested three-mirror system that is commonly used worldwide.
The progressive four-mirror system is supported by a group of optics experts led by Su Dingqiang, an academic at CAS and former president of the Chinese Astronomical Society.
In most large telescopes, a large primary mirror captures light and reflects it off one or two secondary mirrors to the telescope's instruments. The daring design supported by Su calls for four mirrors - one primary and three secondary.
A letter co-authored by Su and Cui Xiangqun, another CAS academic, released online through the Zhishifenzi WeChat public account on Tuesday, stated that "there is no particularly immature technology or at least as many technological risks for the four-mirror construction plan for the new 12-meter telescope than the three-mirror plan."
The Tuesday letter by Su and Cui was a response to a letter in opposition by Chen Jiansheng, an astronomy professor and CAS academician on Friday, news site thepaper.cn reported on Tuesday.
Chen argued "we should try to adopt the most mature technology to make sure the success of construction … all the 10-meter class telescopes in the world are three-mirror systems."
Chen maintains that the three-mirror system can better live up to the scientific needs with more efficiency. While the four-mirror plan is able to get better quality images, it will be easily affected by environmental conditions such as atmospheric turbulence. Chen concluded the core of the debate is whether the 12-meter telescope is scientific needs-oriented or technology-oriented.
The Nanjing Institute of Astronomical Optics & Technology refused to comment on the letters, saying that Su and Cui were expressing personal opinions and were not speaking for the institute.
