astronomy

Julius von Hann

Julius von Hann 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 Julius von Hann rather than just read about it. In short: Julius Ferdinand von Hann (23 March 1839 in Wartberg ob der Aist near Linz – 1 October 1921 in Vienna) was an Austrian meteorologist. He is seen as a father of modern meteorology.

Key takeaways

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

Reference excerpt

Julius Ferdinand von Hann (23 March 1839 in Wartberg ob der Aist near Linz – 1 October 1921 in Vienna) was an Austrian meteorologist. He is seen as a father of modern meteorology.

Biography He was educated at the gymnasium of Kremsmünster and then studied mathematics, chemistry and physics at the University of Vienna, then geology and paleontology under Eduard Suess and physical geography under Friedrich Simony. From 1865 to 1868, he was master at the Oberrealschule at Linz, and in 1865 was invited by Karl Jelinek to become the first editor of the Zeitschrift für Meteorologie. In 1877, he succeeded Jelinek as the director of the Meteorologische Zentralanstalt (Central Institute for Meteorology and Earth Magnetism) and was appointed professor of meteorology at the University of Vienna. In 1897, he retired as director and became professor of meteorology at the University of Graz, but returned to Vienna to fill the chair of professor of cosmic physics in 1900, where he remained until 1910. He became an international honorary member of the American Academy of Arts and Sciences in 1902. In 1912, he was made a foreign knight of the Prussian Ordre Pour le Mérite.

Hann window Hann invented a weighted moving average technique for combining meteorological data from neighboring regions, using the weights [1/4, 1/2, 1/4], known as Hann smoothing. In signal processing, the Hann window is a window function, called the Hann function, derived from this technique by R. B. Blackman and John Tukey in 1959. Here, the use of the Hann window is called "hanning", e.g., "hanning" a signal is to apply the Hann window to it.

Works Die Erde als Ganzes, ihre Atmosphäre und Hydrosphäre, 1872, 5th edition 1896 Handbuch der Klimatologie, first issued 1883, revised editions until 1911 Handbook of Climatology. Part I. General Climatology. Macmillan. 1903; translated by Robert DeCourcy Ward{{cite book}}: CS1 maint: postscript (link) Atlas der Meteorologie, 1887 Allgemeine Erdkunde. Ein Leitfaden der astronomischen Geographie, Meteorologie, Geologie und Biologie, 5th edition 1896 Lehrbuch der Meteorologie, 1901, 3rd edition 1915 He contributed many papers to the Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften.

Notes

References

Chisholm, Hugh, ed. (1922). "Hann, Julius von" . Encyclopædia Britannica (12th ed.). London & New York: The Encyclopædia Britannica Company. "Hann, Julius Ferdinand von." Complete Dictionary of Scientific Biography. 2008. Encyclopedia.com. (June 26, 2014). [1]

Illustrations

Worked examples

Example 1 — a first encounter with Julius von Hann

Start with the simplest possible case. Write down what Julius von Hann 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 Julius von Hann 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 Julius von Hann 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 Julius von Hann

In research: Julius von Hann 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 Julius von Hann 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: Julius von Hann is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1839 births, 1921 deaths, Academic staff of the University of Vienna, so understanding it makes those chapters shorter.
In everyday life: Look for Julius von Hann 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 Julius von Hann in 20 minutes

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

Frequently asked questions

What is Julius von Hann in simple terms?

Julius Ferdinand von Hann (23 March 1839 in Wartberg ob der Aist near Linz – 1 October 1921 in Vienna) was an Austrian meteorologist. He is seen as a father of modern meteorology.

Why does Julius von Hann 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 Julius von Hann?

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 Julius von Hann.