astronomy

Harold Johnson (astronomer)

Harold Johnson (astronomer) 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 Harold Johnson (astronomer) rather than just read about it. In short: Harold Lester Johnson (April 17, 1921 – April 2, 1980) was an American astronomer. Harold Johnson was born in Denver, Colorado, on April 17, 1921.

Key takeaways

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

Reference excerpt

Harold Lester Johnson (April 17, 1921 – April 2, 1980) was an American astronomer. Harold Johnson was born in Denver, Colorado, on April 17, 1921. He received his early education in Denver public schools and went to the University of Denver, graduating with a degree in mathematics in 1942. Johnson was recruited by the MIT Radiation Laboratory to work on World War II related radar research. After the war Johnson began graduate studies in astronomy at University of California, Berkeley where he completed his thesis under Harold Weaver in 1948. In the following years working at Lowell Observatory, University of Wisconsin–Madison, Yerkes Observatory (where he met William Wilson Morgan), McDonald Observatory, University of Texas–Austin, the Lunar and Planetary Laboratory in Tucson, Arizona, and the National Autonomous University of Mexico he applied his instrumental and electronic talents to developing and calibrating astronomical photoelectric detectors. He died of a heart attack in Mexico City in 1980. He and his wife, Mary Elizabeth Jones, had two children. Johnson was awarded the Helen B. Warner Prize by the American Astronomical Society in 1956. He was elected to the National Academy of Sciences in 1969. He is remembered for introducing the UBV photometric system (also called the Johnson or Johnson-Morgan system), along with William Wilson Morgan in 1953, which he later expanded also with infrared filters in the 1960s.

External links Gérard Henri de Vaucouleurs (1995). "Harold Lester Johnson: A Biographical Memoir" (PDF). National Academy of Sciences. Archived (PDF) from the original on March 26, 2019.

References

Worked examples

Example 1 — a first encounter with Harold Johnson (astronomer)

Start with the simplest possible case. Write down what Harold Johnson (astronomer) 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 Harold Johnson (astronomer) 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 Harold Johnson (astronomer) 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 Harold Johnson (astronomer)

In research: Harold Johnson (astronomer) 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 Harold Johnson (astronomer) 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: Harold Johnson (astronomer) is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1921 births, 1980 deaths, 20th-century American astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Harold Johnson (astronomer) 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 Harold Johnson (astronomer) in 20 minutes

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

Frequently asked questions

What is Harold Johnson (astronomer) in simple terms?

Harold Lester Johnson (April 17, 1921 – April 2, 1980) was an American astronomer. Harold Johnson was born in Denver, Colorado, on April 17, 1921.

Why does Harold Johnson (astronomer) 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 Harold Johnson (astronomer)?

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 Harold Johnson (astronomer).