astronomy

NGC 23

NGC 23 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 23 rather than just read about it. In short: NGC 23 is a spiral galaxy located in the northern constellation of Pegasus, around 173.5 megalight-years distant from the Milky Way. It was discovered by William Herschel on 10 September 1784.

Key takeaways

NGC 23 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 23 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 23 from memory before moving on to harder problems.

Reference excerpt

NGC 23 is a spiral galaxy located in the northern constellation of Pegasus, around 173.5 megalight-years distant from the Milky Way. It was discovered by William Herschel on 10 September 1784. In the Webb Society Deep-Sky Observer's Handbook, the visual appearance of NGC 23 is described as follows:

Bright, extended ellipse; a bright nuclear structure is noticeably elongated; two weak spiral enhancements emerge from opposite sides of the nucleus, one curving towards a bright star attached on the south end. The galaxy is likely interacting with NGC 9.

The shape of this galaxy is described by its morphological classification of SBb, which indicates it is a barred spiral (SB) with spiral arms that are moderately tightly wound (b). It is a luminous infrared galaxy with star-forming clumps.

NGC 23 group NGC 23 is part of the NGC 23 group (also known as LGG 2) that includes at least 6 other galaxies: NGC 1, NGC 26, UGC 69, UGC 79, UGC 110, and UGC 127.

Supernova One supernova has been observed in NGC 23. SN 1955C (type unknown, mag. 16) was discovered by Allan Sandage in September 1958 using the Hale Telescope. On a photographic plate taken 23 October 1955 (three years prior), a bright star with a visual magnitude around 16 was located 10″ to the north and 10″ east of the galactic center. The star was not visible on a photograph taken 60 days prior.

See also NGC List of NGC objects (1–1000) List of NGC objects Galaxy

References

External links Media related to NGC 23 at Wikimedia Commons

NGC 23 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 23

Start with the simplest possible case. Write down what NGC 23 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 23 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 23 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 23

In research: NGC 23 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 23 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 23 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Barred spiral galaxies, Discoveries by William Herschel, Galaxies discovered in 1784, so understanding it makes those chapters shorter.
In everyday life: Look for NGC 23 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 23 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 23 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 23 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 23 in simple terms?

NGC 23 is a spiral galaxy located in the northern constellation of Pegasus, around 173.5 megalight-years distant from the Milky Way. It was discovered by William Herschel on 10 September 1784.

Why does NGC 23 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 23?

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 23.