astronomy

LAMOST

LAMOST 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 LAMOST rather than just read about it. In short: The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), also known as the Guo Shoujing Telescope (Chinese: 郭守敬望远镜) after the 13th-century Chinese astronomer, is a meridian reflecting Schmidt telescope, located in Xinglong Station, Hebei Province, China. Undertaken by the Chinese Academy of Sciences, the telescope is planned to conduct a 5-year spectroscopic survey of 10 million Milky Way stars, as we…

Key takeaways

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

Reference excerpt

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), also known as the Guo Shoujing Telescope (Chinese: 郭守敬望远镜) after the 13th-century Chinese astronomer, is a meridian reflecting Schmidt telescope, located in Xinglong Station, Hebei Province, China. Undertaken by the Chinese Academy of Sciences, the telescope is planned to conduct a 5-year spectroscopic survey of 10 million Milky Way stars, as well as millions of galaxies. The project's budget is RMB 235 million yuan.

Optics LAMOST is configured as a reflective Schmidt telescope with active optics. There are two mirrors, each made up of a number of 1.1-metre (p-p) hexagonal deformable segments. The first mirror, MA (24 segments, fitting in a 5.72×4.4 m rectangle) is a Schmidt corrector plate in a dome at ground level. The almost-flat mirror MA reflects the light to the south, up a large slanted tunnel (25° above horizontal) to the larger spherical focusing mirror MB (37 segments, fitting in a 6.67×6.09 m rectangle). This directs light to a focal plane 1.75 metres in diameter corresponding to a five-degree field of view. The focal plane is tiled with 4000 fiber-positioning units, each feeding an optical fiber which transfers light to one of sixteen 250-channel spectrographs below. Looking at the image opposite, MB is at the top of the left-hand supporting column of the tower, MA is in the left of the two domes at the right of the image (the rightmost, grey dome is an unrelated telescope), and the spectrographs are inside the right-hand column of the tower. Each spectrograph has two 4k×4k CCD cameras, using e2v CCD chips, with 'blue' (370–590 nm) and 'red' (570–900 nm) sides; the telescope can also be used in a higher spectral resolution mode where the range is 510–540 and 830–890 nm. The telescope uses active optics to control its reflecting corrector, resulting in it combining a large aperture with a wide field of view. The available large focal plane may accommodate up to thousands of fibers, by which the collected light of celestial objects down to 20.5 magnitude is fed into the spectrographs, resulting in a spectrum acquiring rate of ten-thousands of spectra per night.

Scientific goals The telescope is to conduct a wide-field survey, called the "LAMOST Experiment for Galactic Understanding and Evolution," or LEGUE. Particular scientific goals of the LAMOST include:

An extra-galactic spectroscopic survey to shed light on the large scale structure of the universe A stellar spectroscopic survey, including a search for metal-poor stars in the galactic halo, to provide information on the structure of our Galaxy Cross-identification of multi-waveband surveys It is also hoped that the vast volume of data produced will lead to additional serendipitous discoveries. Early commissioning observations have been able to confirm spectroscopically a new method of identifying quasars based on their infrared color. An overarching goal of the telescope is to bring Chinese astronomy into the 21st century, taking a leading role in wide-field spectroscopy and in the fields of large-scale and large-sample astronomy and astrophysics.

Early results A 2011 conference presentation suggests that there was initially a problem with accuracy of the fiber positioners causing poor throughput, but that this was rectified by adding another calibration step. The same presentation also points out that the telescope's location, only 115 km (71 mi) NW of Beijing, is far from ideal, being in an area with high levels of both atmospheric and light pollution. The telescope has generally been disappointing, with the site receiving only 120 clear nights per year. The first LAMOST data release occurred in June 2013 (DR1). Subsequent data releases occurred in 2014 (DR2), 2015 (DR3), 2016 (DR4), 2017 (DR5), 2018 (DR6), 2019 (DR7), and the most recent data release, DR8, occurred in May 2020.

See also List of largest optical reflecting telescopes

References

External links Homepage of LAMOST The First Data Release (DR1) of the LAMOST general survey (May, 2015)

Illustrations

Worked examples

Example 1 — a first encounter with LAMOST

Start with the simplest possible case. Write down what LAMOST 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 LAMOST 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 LAMOST 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 LAMOST

In research: LAMOST 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 LAMOST 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: LAMOST is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buildings and structures in Hebei, Chinese telescopes, Guo Shoujing, so understanding it makes those chapters shorter.
In everyday life: Look for LAMOST 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 LAMOST in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LAMOST 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 LAMOST out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LAMOST in simple terms?

Why does LAMOST 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 LAMOST?

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 LAMOST.