astronomy

NGC 4

NGC 4 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 NGC 4 rather than just read about it. In short: NGC 4 is a lenticular galaxy with the morphological type of S0-a, located in the constellation of Pisces. NGC 4 was discovered by Albert Marth on 29 November 1864 using a 48-inch reflecting telescope.

Key takeaways

NGC 4 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NGC 4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 4 from memory before moving on to harder problems.

Reference excerpt

NGC 4 is a lenticular galaxy with the morphological type of S0-a, located in the constellation of Pisces. NGC 4 was discovered by Albert Marth on 29 November 1864 using a 48-inch reflecting telescope.

Observational History NGC 4 was first observed by Albert Marth on 29 November 1864 on the same night NGC 3 was discovered. NGC 4 was described as "extremely faint". NGC 4 is about 4.7 arcminutes northeast of NGC 3 and about 2.9 arcminutes west of a G-type star BD+07 1.

PGC 620

PGC 620 was a galaxy in the Lyon-Meudon Extragalactic Database which designated PGC 620 as NGC 4 because the catalogers didn't realize that Marth could see an object as faint as NGC 4. Marth was using a telescope with a 48-inch aperture, and could see a 16th-magnitude galaxy. The error in the LEDA database has been corrected and the galaxy was designated as PGC 212468 for NGC 4, with its incorrect identification as PGC 620 noted immediately below as a warning.

Properties NGC 4 is a lenticular galaxy with an approximated distance of 406 million light years and an approximated size of 59,000 light years across, both of these having a high degree of uncertainty

Gallery

References

Illustrations

Worked examples

Example 1 — a first encounter with NGC 4

Start with the simplest possible case. Write down what NGC 4 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 NGC 4 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 NGC 4 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 NGC 4

In research: NGC 4 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 NGC 4 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: NGC 4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1864, LEDA objects, Lenticular galaxies, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 4 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 NGC 4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 4 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 NGC 4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 4 in simple terms?

Why does NGC 4 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 NGC 4?

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 NGC 4.