astronomy

NGC 247

NGC 247 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 247 rather than just read about it. In short: NGC 247 (also known as Caldwell 62 and commonly known as the Claw Galaxy) is an intermediate spiral galaxy about 11.1 Mly away in the constellation Cetus. This distance was confirmed in late February 2011.

Key takeaways

NGC 247 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 247 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 247 from memory before moving on to harder problems.

Reference excerpt

NGC 247 (also known as Caldwell 62 and commonly known as the Claw Galaxy) is an intermediate spiral galaxy about 11.1 Mly away in the constellation Cetus. This distance was confirmed in late February 2011. Previous measurements showed that the galaxy was about 12.2 Mly away, but this was proved to be wrong. NGC 247 is a member of the Sculptor Group, and is 70 000 light years in diameter. NGC 247 has an unusually large void on one side of its spiral disk. This void contains some older, redder stars but no younger, bluer stars.

Nearby galaxies and galaxy group information NGC 247 is one of several galaxies that is gravitationally bound to the Sculptor Galaxy (NGC 253). These galaxies form a small core in the center of the Sculptor Group, which is one of the nearest groups of galaxies to the Milky Way. Most other galaxies associated with the Sculptor Group are only weakly gravitationally bound to this core.

Burbidge's Chain In 1963, Geoffrey Burbidge and Margaret Burbidge identified a group of five background galaxies located northeast of NGC 247. This grouping came to be known as Burbidge's Chain, and in 1977 it was listed in the VV catalog as VV 518. Individually, the 5 galaxies are also identified as NGC 247A, NGC 247B, NGC 247C, NGC 247D, and ESO 540-025.

Image Gallery

See also List of NGC objects (1–1000) Markarian's Chain

References

External links Media related to NGC 247 at Wikimedia Commons NGC 247 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images

Illustrations

Worked examples

Example 1 — a first encounter with NGC 247

Start with the simplest possible case. Write down what NGC 247 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 247 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 247 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 247

In research: NGC 247 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 247 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 247 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1784, Caldwell objects, Cetus (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for NGC 247 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 247 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 247 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 247 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 247 in simple terms?

Why does NGC 247 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 247?

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 247.