engineering

Henri Chrétien

Henri Chrétien is a engineering 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 Henri Chrétien rather than just read about it. In short: Henri Jacques Chrétien (French pronunciation: [ɑ̃ʁi ʒak kʁetjɛ̃]; 1 February 1879, Paris – 6 February 1956, Washington, D.C.) was a French astronomer and an inventor. Born in Paris, France, his most famous inventions are: the anamorphic widescreen process, using an anamorphic lens system called Hypergonar, that resulted in the CinemaScope widescreen technique, and the co-invention, with George Willis Ritchey, of the…

Key takeaways

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

Reference excerpt

Henri Jacques Chrétien (French pronunciation: [ɑ̃ʁi ʒak kʁetjɛ̃]; 1 February 1879, Paris – 6 February 1956, Washington, D.C.) was a French astronomer and an inventor.

Born in Paris, France, his most famous inventions are:

the anamorphic widescreen process, using an anamorphic lens system called Hypergonar, that resulted in the CinemaScope widescreen technique, and the co-invention, with George Willis Ritchey, of the Ritchey–Chrétien telescope, an improved type of astronomical telescope, employing a system now used in virtually all large research telescopes. He spent part of his early astronomical career at the Nice Observatory, which was close to his house, the Villa Paradou. The Villa was built by famous French architect Charles Garnier who also built the Nice Observatory and both the operas of Paris and Monaco. In 1995, the abandoned villa was acquired by the artist Rainer Maria Latzke, who restored it and added new murals to the existing frescoes. Chrétien was one of the founders of the Institut d'optique théorique et appliquée and professor at the French "grande école" SupOptique (École supérieure d'optique).

Awards and honours The astronomical Chrétien International Research Grants awards are in honour of him In 1901, Chrétien, Joseph Joachim Landerer and Thomas David Anderson jointly received the Prix Jules Janssen, the highest award of the Société astronomique de France (French Astronomical Society). Valz Prize from the French Academy of Sciences (1931) The crater Chrétien on the Moon is named in his honour. In 1955, he received an Academy Award for his work on the CinemaScope process The Pavillon Henri Chrétien, an historical building on the Nice Observatory site which is visible from the city of Nice, also bears his name.

Publications ADS NASA Library of Congress Library of Congress

References

Illustrations

Worked examples

Example 1 — a first encounter with Henri Chrétien

Start with the simplest possible case. Write down what Henri Chrétien claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 Henri Chrétien 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 Henri Chrétien 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 Henri Chrétien

In research: Henri Chrétien appears in engineering 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 Henri Chrétien 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: Henri Chrétien is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1879 births, 1956 deaths, 20th-century French astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Henri Chrétien 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Henri Chrétien” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Henri Chrétien in 20 minutes

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

Frequently asked questions

What is Henri Chrétien in simple terms?

Henri Jacques Chrétien (French pronunciation: [ɑ̃ʁi ʒak kʁetjɛ̃]; 1 February 1879, Paris – 6 February 1956, Washington, D.C.) was a French astronomer and an inventor. Born in Paris, France, his most famous inventions are: the anamorphic widescreen process, using an anamorphic lens system called Hyp…

Why does Henri Chrétien matter?

Because it connects several engineering 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 Henri Chrétien?

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 Henri Chrétien.