astronomy

NGC 945

NGC 945 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 945 rather than just read about it. In short: NGC 945 is a barred spiral galaxy in the constellation Cetus, located south of the celestial equator. It is estimated to be 200 million light-years from the Milky Way, and about 135,000 light-years in diameter.

Key takeaways

NGC 945 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 945 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NGC 945 from memory before moving on to harder problems.

Reference excerpt

NGC 945 is a barred spiral galaxy in the constellation Cetus, located south of the celestial equator. It is estimated to be 200 million light-years from the Milky Way, and about 135,000 light-years in diameter. The object was discovered by astronomer William Herschel on November 28, 1785. It is near NGC 948, with which it forms a gravitationally bound pair of galaxies. In the same area of the sky there are the galaxies NGC 942, NGC 943, NGC 950, and IC 230.

NGC 948 NGC 948 is a spiral galaxy located extremely close to NGC 945. Its speed relative to the cosmic microwave background is 4,259 ± 17 km/s, which corresponds to a Hubble distance of 62.8 ± 4.4 Mpc (~205 million ly). NGC 948 was discovered by American astronomer Lewis Swift in 1886. The luminosity class of NGC 948 is III and it has a broad HI line. With a surface brightness equal to 14.17 mag/am2, NGC 948 is classified as a low surface brightness galaxy (LSB).

Supernovae Two supernovae have been observed in NGC 945:

SN 1998dt (Type Ib, mag. 17.7) was discovered by T. Shefler of the University of California at Berkeley on 1 September 1998, as part of the LOSS (Lick Observatory Supernova Search) program at the Lick observatory. SN 2020obd (Type II, mag. 17.3) was discovered by ATLAS on 6 July 2020.

NGC 945 group NGC 945 is the brightest galaxy in a group of at least 7 members that bears its name. The other six galaxies in the NGC 945 group are NGC 948, NGC 950, NGC 977, MCG -2-7-20, MCG -2-7-32 and MCG -2-7-337.

See also Interacting galaxy List of NGC objects (1–1000) Lists of galaxies

References

External links NGC 945 at SIMBAD NGC 948 at SIMBAD

Illustrations

Worked examples

Example 1 — a first encounter with NGC 945

Start with the simplest possible case. Write down what NGC 945 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 945 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 945 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 945

In research: NGC 945 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 945 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 945 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Astronomical objects discovered in 1785, Barred spiral galaxies, Cetus (constellation), so understanding it makes those chapters shorter.
In everyday life: Look for NGC 945 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 945 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NGC 945 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 945 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NGC 945 in simple terms?

Why does NGC 945 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 945?

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 945.