astronomy

Purple Mountain Observatory

Purple Mountain Observatory is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Purple Mountain Observatory rather than just read about it. In short: Purple Mountain Observatory, also known as Zijinshan Astronomical Observatory, is a dual-use astronomical observatory operated by the Chinese Academy of Sciences (CAS) and the People's Liberation Army Aerospace Force (PLAASF). It is headquartered at Purple Mountain, east of Nanjing, with off-site sensor installations located across the country.

Key takeaways

Purple Mountain Observatory belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Purple Mountain Observatory to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Purple Mountain Observatory from memory before moving on to harder problems.

Reference excerpt

Purple Mountain Observatory, also known as Zijinshan Astronomical Observatory, is a dual-use astronomical observatory operated by the Chinese Academy of Sciences (CAS) and the People's Liberation Army Aerospace Force (PLAASF). It is headquartered at Purple Mountain, east of Nanjing, with off-site sensor installations located across the country. The observatory has a very active open science role, serving as China's primary contribution to the Inter-Agency Space Debris Coordination Committee, global asteroid impact avoidance efforts, and calculating the official Chinese calendar. Since the early 2000s, the observatory has gained a significant classified intelligence role, serving as China's primary optical space domain awareness capability. At least part of the military component is operated by PLAASF Base 26 as the Space Target and Debris Observation and Research Center.

History

The Purple Mountain Observatory was established in 1934 funded by the Nationalist Government of the Republic of China and administered by Academia Sinica. The longtime director of the observatory from 1950 to 1984 was Chinese astronomer Zhang Yuzhe. By the late 1980s, increasing light pollution in Nanjing meant Purple Mountain was no longer viable as a working observatory. It has since shifted its focus to public education, with much of the actual scientific work being carried out in its five branch observatories located at Qinghai (in Delingha), Ganyu, Xuyi, Honghe (in Jiamusi), and Qingdao. The Minor Planet Center credits the observatory with the discovery of 149 minor planets between 1955 and 1983, while the observatory's PMO NEO Survey Program is credited with more than 600 discoveries between 2006 and 2013. In August 2026, it was reported that the New Zealand Security Intelligence Service disrupted a plan by Purple Mountain Observatory to install ground-based space infrastructure in New Zealand that could collect intelligence of military value.

Discoveries The observatory discovered the periodic comets 60P/Tsuchinshan and 62P/Tsuchinshan, as well as the non-periodic C/1977 V1 (Tsuchinshan), also known as Comet 1977 X, C/2017 E2, and C/2023 A3 (Tsuchinshan-ATLAS). They are named after the postal romanization of the name (Wade–Giles: Tzu-chin-shan; pinyin: Zǐjīnshān). Many asteroids were also discovered, including the Trojan asteroids 2223 Sarpedon, 2260 Neoptolemus, 2363 Cebriones, 2456 Palamedes, and the eponymous 3494 Purple Mountain.

Near-Earth object survey The Chinese Near-Earth Object Survey (CNEOS), based at the Xuyi Station (D29) in Xuyi, Jiangsu, started observations in 2006. It uses a 1:04=1:20=1:80 m Schmidt telescope equipped with a 4K × 4K CCD detector with the drift-scanning function. As of August 2012, the program has observed 149,971 asteroids, found 1,279 new provisional designation asteroids, and cataloged 251 numbered asteroids including five Jupiter trojans, two Hildian, and one Phocaea asteroid. The program has also observed the position of 824 near-Earth objects (NEOs) and discovered four new ones: the Apollo asteroid (285339) 1999 JR6, and the three Amor asteroid (410195) 2007 RT147, (388567) 2007 QX14, and (468681) 2009 MZ6.

List of discovered minor planets (1955–1983)

A total of 149 minor planets were discovered by the Purple Mountain Observatory between 1955 and 1983.

List of discoveries by the PMO NEO Survey Program

Several hundred minor planets were discovered by the observatory's PMO NEO Survey Program from 2006 to 2013.

Image gallery

See also List of astronomical observatories Liu Caipin Wang Sichao

Notes

References

External links

Purple Mountain Observatory website (in English and Chinese)

Illustrations

Worked examples

Example 1 — a first encounter with Purple Mountain Observatory

Start with the simplest possible case. Write down what Purple Mountain Observatory claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Purple Mountain Observatory before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Purple Mountain Observatory ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Purple Mountain Observatory

In research: Purple Mountain Observatory appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Purple Mountain Observatory in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Purple Mountain Observatory is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical observatories in China, Buildings and structures in Nanjing, Discoveries by the PMO NEO Survey Program, so understanding it makes those chapters shorter.
In everyday life: Look for Purple Mountain Observatory outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Purple Mountain Observatory in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Purple Mountain Observatory means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Purple Mountain Observatory out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Purple Mountain Observatory in simple terms?

Why does Purple Mountain Observatory matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Purple Mountain Observatory?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Purple Mountain Observatory.