astronomy

Per Collinder

Per Collinder 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 Per Collinder rather than just read about it. In short: Dr. Per Arne Collinder (22 May 1890 – 6 December 1975) was a Swedish astronomer, cartographer, and navigator.

Key takeaways

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

Reference excerpt

Dr. Per Arne Collinder (22 May 1890 – 6 December 1975) was a Swedish astronomer, cartographer, and navigator. Collinder was born in Sundsvall in 1890. Despite his astronomical career being most famous, his professional life was as a surveyor in the Arctic ocean. He served as surveyor and cartographer for the Swedish Royal Hydrographic Office from 1914-1937. He then became head of the Swedish Bureau of Nautical Instruments from 1937-1945, and then President of the Swedish Compass Adjusters' Association. He is best known for a catalog of open clusters that he published in 1931, which is today known as the Collinder catalogue. He wrote the books History of navigation and Worlds in Orbit. He was married twice, and his first wife gave him four children. Collinder died at Uppsala.

Notes and references

Worked examples

Example 1 — a first encounter with Per Collinder

Start with the simplest possible case. Write down what Per Collinder 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 Per Collinder 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 Per Collinder 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 Per Collinder

In research: Per Collinder 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 Per Collinder 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: Per Collinder is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1890 births, 1974 deaths, 20th-century Swedish astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Per Collinder 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 Per Collinder in 20 minutes

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

Frequently asked questions

What is Per Collinder in simple terms?

Dr. Per Arne Collinder (22 May 1890 – 6 December 1975) was a Swedish astronomer, cartographer, and navigator.

Why does Per Collinder 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 Per Collinder?

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 Per Collinder.